Paget’s Disease of Bone

Overview

Definition

Paget’s disease of bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types (PDB, also known as osteitis deformans) is a disorder of bone metabolism Bone metabolism Bone is the primary storage site of calcium in the body; thus, bone metabolism plays a critical role in maintaining normal calcium levels. Bone metabolism (and thus calcium levels) are primarily regulated by 3 hormones, namely, calcitonin, parathyroid hormone (PTH), and vitamin D. Calcium Hemostasis and Bone Metabolism affecting the aging skeleton.

Epidemiology

• 2nd most common metabolic bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types disorder, after osteoporosis Osteoporosis Osteoporosis refers to a decrease in bone mass and density leading to an increased number of fractures. There are 2 forms of osteoporosis: primary, which is commonly postmenopausal or senile; and secondary, which is a manifestation of immobilization, underlying medical disorders, or long-term use of certain medications. Osteoporosis
• Most common after 55 years of age
• 3:2 male predominance
• Geographic variations in prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency:
  • United States: 1% of population > 40 years old
  • Most common in Europe (except Scandinavia), Australia, and New Zealand, with an average of 3%–4%, and ranges from 2%–9%
  • Rare in Asia ASIA Spinal Cord Injuries
• Positive family history Family History Adult Health Maintenance: in 12%–40% of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship 
• Asymptomatic in 70% of cases
• Overall, the incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency is declining.

Etiology

• Uncertain: genetic and infectious etiologies Infectious Etiologies High-Risk Headaches implicated and likely additive
• Genetic:
  • Autosomal dominant inheritance Autosomal dominant inheritance Autosomal Recessive and Autosomal Dominant Inheritance with variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables penetrance Penetrance The percent frequency with which a dominant or homozygous recessive gene or gene combination manifests itself in the phenotype of the carriers. Familial Juvenile Polyposis
  • Mutations of genes Genes A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. DNA Types and Structure SQSTM1, RANK, and regions of chromosomes Chromosomes In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. DNA Types and Structure 5 and 6 are all involved in bone metabolism Bone metabolism Bone is the primary storage site of calcium in the body; thus, bone metabolism plays a critical role in maintaining normal calcium levels. Bone metabolism (and thus calcium levels) are primarily regulated by 3 hormones, namely, calcitonin, parathyroid hormone (PTH), and vitamin D. Calcium Hemostasis and Bone Metabolism.
  • Germline mutations in SQSTM1:
    • Approximately 40% of the PDB familial cases
    • Approximately 10% of sporadic Sporadic Selective IgA Deficiency cases
• Viral infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease:
  • Less well established than genetic etiologies
  • Substantial evidence for possible measles Measles Measles (also known as rubeola) is caused by a single-stranded, linear, negative-sense RNA virus of the family Paramyxoviridae. It is highly contagious and spreads by respiratory droplets or direct-contact transmission from an infected person. Typically a disease of childhood, measles classically starts with cough, coryza, and conjunctivitis, followed by a maculopapular rash. Measles Virus infection of osteoclasts Osteoclasts A large multinuclear cell associated with the bone resorption. An odontoclast, also called cementoclast, is cytomorphologically the same as an osteoclast and is involved in cementum resorption. Bones: Development and Ossification
  • Measle vaccination Vaccination Vaccination is the administration of a substance to induce the immune system to develop protection against a disease. Unlike passive immunization, which involves the administration of pre-performed antibodies, active immunization constitutes the administration of a vaccine to stimulate the body to produce its own antibodies. Vaccination may explain the declining incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency of PBD.

Pathophysiology

Pathogenesis

• A disease of osteoclasts Osteoclasts A large multinuclear cell associated with the bone resorption. An odontoclast, also called cementoclast, is cytomorphologically the same as an osteoclast and is involved in cementum resorption. Bones: Development and Ossification
• Osteoclast activity accelerates the rate of bone remodeling Bone remodeling The continuous turnover of bone matrix and mineral that involves first an increase in bone resorption (osteoclastic activity) and later, reactive bone formation (osteoblastic activity). The process of bone remodeling takes place in the adult skeleton at discrete foci. The process ensures the mechanical integrity of the skeleton throughout life and plays an important role in calcium homeostasis. An imbalance in the regulation of bone remodeling’s two contrasting events, bone resorption and bone formation, results in many of the metabolic bone diseases, such as osteoporosis. Bones: Remodeling and Healing, causing overgrowth and impaired structural integrity of affected bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types.
• This is followed by increased osteoblast activity.
• Result is enlarged and thickened, but deformed and weakened, bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types.
• Only some areas of bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types are affected, for unknown reasons.
• 3 sequential phases of PDB:
  1. Initial osteolytic stage: predominant osteoclast activity
  2. Mixed osteoclastic-osteoblastic stage
  3. Burned-out quiescent osteosclerotic stage: Osteoblast activity predominates. 

PDB osteoclasts Osteoclasts A large multinuclear cell associated with the bone resorption. An odontoclast, also called cementoclast, is cytomorphologically the same as an osteoclast and is involved in cementum resorption. Bones: Development and Ossification

• Have unique characteristics:
  • Markedly increased number during the active osteolytic phase
  • Atypical/bizarre appearance, with numerous nuclei (up to 100 compared with 10–12 normally)
  • Intranuclear inclusions Intranuclear inclusions Circumscribed masses of foreign or metabolically inactive materials, within the cell nucleus. Some are viral inclusion bodies. Varicella-Zoster Virus/Chickenpox present in some
  • Hypersensitivity to vitamin D Vitamin D A vitamin that includes both cholecalciferols and ergocalciferols, which have the common effect of preventing or curing rickets in animals. It can also be viewed as a hormone since it can be formed in skin by action of ultraviolet rays upon the precursors, 7-dehydrocholesterol and ergosterol, and acts on vitamin D receptors to regulate calcium in opposition to parathyroid hormone. Fat-soluble Vitamins and their Deficiencies
• 2 essential cytokines Cytokines Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner. Adaptive Immune Response required for osteoclast differentiation:
  • Macrophage colony-stimulating factor Macrophage colony-stimulating factor A mononuclear phagocyte colony-stimulating factor (M-CSF) synthesized by mesenchymal cells. The compound stimulates the survival, proliferation, and differentiation of hematopoietic cells of the monocyte-macrophage series. M-CSF is a disulfide-bonded glycoprotein dimer with a mw of 70 kda. It binds to a specific high affinity receptor. White Myeloid Cells: Histology ( M-CSF M-CSF A mononuclear phagocyte colony-stimulating factor (M-CSF) synthesized by mesenchymal cells. The compound stimulates the survival, proliferation, and differentiation of hematopoietic cells of the monocyte-macrophage series. M-CSF is a disulfide-bonded glycoprotein dimer with a mw of 70 kda. It binds to a specific high affinity receptor. White Myeloid Cells: Histology)
  • Receptor Receptor Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors activator of nuclear factor-κB ligand (RANKL)
• Differentiation is inhibited by osteoprotegerin Osteoprotegerin A secreted member of the tnf receptor superfamily that negatively regulates osteoclastogenesis. It is a soluble decoy receptor of rank ligand that inhibits both cell differentiation and function of osteoclasts by inhibiting the interaction between rank ligand and receptor activator of nuclear factor-kappa b. Osteoporosis (OPG; a soluble decoy receptor Receptor Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors for RANKL) and modulated by other cytokines Cytokines Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner. Adaptive Immune Response and hormones Hormones Hormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types.
• Abnormalities of these pathways form the basis for the genetic etiology of PDB.

Gross pathology

• Most common sites:
  • Skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull: Anatomy
  • Thoracolumbar spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy
  • Pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy 
  • Long bones Long bones Length greater than width. Bones: Structure and Types of the lower extremities
  • Axial Axial Computed Tomography (CT) skeleton or proximal femur is involved in 80% of cases.
• Monostotic in 15% of cases; polyostotic in 85%
• Focally enlarged and deformed bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types 
• Irregular thickening of both cortical and cancellous bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types

Microscopic pathology

• Osteolytic phase:
  • Numerous resorption pits
  • Osteoclasts Osteoclasts A large multinuclear cell associated with the bone resorption. An odontoclast, also called cementoclast, is cytomorphologically the same as an osteoclast and is involved in cementum resorption. Bones: Development and Ossification increased in number and aberrant
• Mixed phase:
  • Many bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types surfaces lined by plump osteoblasts Osteoblasts Bone-forming cells which secrete an extracellular matrix. Hydroxyapatite crystals are then deposited into the matrix to form bone. Bones: Development and Ossification
  • Loose connective tissue Loose connective tissue Connective Tissue: Histology, osteoprogenitor cells, and numerous blood vessels adjacent to new bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types
  • Woven bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types becomes lamellar with a mosaic pattern.
  • Porous cortex
  • Thickened, but structurally unsound, trabecular structure
  • Evolves into an osteosclerotic phase, with some osteoblasts Osteoblasts Bone-forming cells which secrete an extracellular matrix. Hydroxyapatite crystals are then deposited into the matrix to form bone. Bones: Development and Ossification and few osteoclasts Osteoclasts A large multinuclear cell associated with the bone resorption. An odontoclast, also called cementoclast, is cytomorphologically the same as an osteoclast and is involved in cementum resorption. Bones: Development and Ossification remaining in mosaic-patterned bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types.
• Sclerotic phase Sclerotic Phase Hypertensive Retinopathy (pathognomonic of PDB):
  • Mosaic pattern of lamellar bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types
  • Looks like a jigsaw puzzle
  • Prominent cement lines joining randomly oriented units of lamellar bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types 

Clinical Presentation

Over 70% of cases are asymptomatic.

Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways

• Transmitted by periosteal nerves and is due to:
  •   Bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types overgrowth
  •  Hyperemia
  •  Microfractures
• Dull, aching type of pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
• Constant, day and night 
• Worse in weight-bearing bones

Bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types deformities and fractures

Sites involved rarely change over a patient’s lifetime.

• Head:
  • Enlarged skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull: Anatomy with frontal bossing Frontal Bossing Hydrocephalus in Children
  • Dilated scalp veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology
  • Basilar invagination (i.e., the tip of the odontoid process is above the foramen magnum) 
  • Jaw Jaw The jaw is made up of the mandible, which comprises the lower jaw, and the maxilla, which comprises the upper jaw. The mandible articulates with the temporal bone via the temporomandibular joint (TMJ). The 4 muscles of mastication produce the movements of the TMJ to ensure the efficient chewing of food. Jaw and Temporomandibular Joint: Anatomy deformity Deformity Examination of the Upper Limbs, malocclusion, and periodontal disease 
  • Angioid streaks (cracks in Bruch’s membranes of the eyes, can cause choroidal neovascularization Choroidal Neovascularization A pathological process consisting of the formation of new blood vessels in the choroid. Macular Degeneration)
• Spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy and pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy:
  • Compression Compression Blunt Chest Trauma fractures
  • Pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy:
    • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
    • Arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis 
    • Protrusio acetabuli Protrusio Acetabuli Marfan Syndrome (femoral head projects medial to the ilioischial line)
• Long bones Long bones Length greater than width. Bones: Structure and Types: 
  • Bowing deformities, with arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis of adjacent joints
  • Fractures:
    • Transverse fracture Transverse Fracture Overview of Bone Fractures at the lesser trochanter of femur the most common
    • The most common complication in long bones Long bones Length greater than width. Bones: Structure and Types
    • Blood loss increased due to increased vascularity
    • Casting or immobility can cause severe osteopenia Osteopenia Osteoporosis. 
  • Skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions overlying bones: warm due to increased vascularity in bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types

Complications of bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types overgrowth

• Neurologic:
  • Hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss and  dizziness Dizziness An imprecise term which may refer to a sense of spatial disorientation, motion of the environment, or lightheadedness. Lateral Medullary Syndrome (Wallenberg Syndrome) (due to vestibulocochlear nerve Vestibulocochlear nerve The 8th cranial nerve. The vestibulocochlear nerve has a cochlear part (cochlear nerve) which is concerned with hearing and a vestibular part (vestibular nerve) which mediates the sense of balance and head position. The fibers of the cochlear nerve originate from neurons of the spiral ganglion and project to the cochlear nuclei (cochlear nucleus). The fibers of the vestibular nerve arise from neurons of scarpa’s ganglion and project to the vestibular nuclei. The 12 Cranial Nerves: Overview and Functions and cochlear involvement)
  • Hydrocephalus Hydrocephalus Excessive accumulation of cerebrospinal fluid within the cranium which may be associated with dilation of cerebral ventricles, intracranial. Subarachnoid Hemorrhage
  • Instability of gait Gait Manner or style of walking. Neurological Examination
  • Dementia Dementia Major neurocognitive disorders (NCD), also known as dementia, are a group of diseases characterized by decline in a person’s memory and executive function. These disorders are progressive and persistent diseases that are the leading cause of disability among elderly people worldwide. Major Neurocognitive Disorders from vascular steal due to bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types vascularity 
  • Spinal stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS)
  • Spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage: due to vascular steal 
  • Radiculopathies ( nerve compression Nerve Compression Brachial Plexus Injuries)
• Metabolic:
  • More common in untreated patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with polyostotic disease
  • High-output heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)
  • Hypercalcemia Hypercalcemia Hypercalcemia (serum calcium > 10.5 mg/dL) can result from various conditions, the majority of which are due to hyperparathyroidism and malignancy. Other causes include disorders leading to vitamin D elevation, granulomatous diseases, and the use of certain pharmacological agents. Symptoms vary depending on calcium levels and the onset of hypercalcemia. Hypercalcemia during immobilization Immobilization Delirium or fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures:
    • Hypercalciuria Hypercalciuria Excretion of abnormally high level of calcium in the urine, greater than 4 mg/kg/day. Nephrolithiasis 
    • Increased risk of kidney stones Kidney stones Nephrolithiasis is the formation of a stone, or calculus, anywhere along the urinary tract caused by precipitations of solutes in the urine. The most common type of kidney stone is the calcium oxalate stone, but other types include calcium phosphate, struvite (ammonium magnesium phosphate), uric acid, and cystine stones. Nephrolithiasis  
• Neoplastic:
  • Occur in < 1% of PDB
  • Risk is higher in polyostotic and long-standing disease.
  • Osteosarcoma Osteosarcoma Osteosarcoma is a primary malignant tumor of the bone characterized by the production of osteoid or immature bone by the tumor cells. The disease is most common in children and young adults and most frequently affects growth plates of the long bones, although it can involve any bone. Osteosarcoma the most common
  • Fibrosarcoma
  • Giant cell tumors:
    • Mostly benign Benign Fibroadenoma
    • Cause local destruction
    • Rarely metastasize

Diagnosis

History

• Elderly patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship 
• Pathologic fractures
• Hypercalcemia Hypercalcemia Hypercalcemia (serum calcium > 10.5 mg/dL) can result from various conditions, the majority of which are due to hyperparathyroidism and malignancy. Other causes include disorders leading to vitamin D elevation, granulomatous diseases, and the use of certain pharmacological agents. Symptoms vary depending on calcium levels and the onset of hypercalcemia. Hypercalcemia after bedrest

Laboratory findings

• Serum alkaline phosphatase Alkaline Phosphatase An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. Osteosarcoma:
  • Often elevated, with normal gamma-glutamyl-transpeptidase (unlike liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy disease)
  • Bone-specific alkaline phosphatase Alkaline Phosphatase An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. Osteosarcoma (bSAP) elevation
• Other markers of bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types turnover:
  • Urinary N-telopeptide crosslink (NTX) 
  • Serum C-telopeptide crosslink (CTX)
  • Amino-terminal propeptide of type I procollagen (PINP)
• Serum calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes and phosphorus:
  • Normal in most patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship
  • May be elevated in cases of fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures or immobility
  • If elevated in an ambulatory patient without fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures, may indicate other pathology (i.e., primary hyperparathyroidism Primary hyperparathyroidism A condition of abnormally elevated output of parathyroid hormone due to parathyroid hyperplasia or parathyroid neoplasms. It is characterized by the combination of hypercalcemia, phosphaturia, elevated renal 1, 25-dihydroxyvitamin d3 synthesis, and increased bone resorption. Hyperparathyroidism)

Imaging

• Most important diagnostic tool
• Plain radiographs:
  • Osteolytic lesions in early PDB: “osteoporosis circumscripta” in the skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull: Anatomy
  • Thickened, denser, and enlarged bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types as osteoblast activity increases
  • Mixed lytic/sclerotic lesions, with flame-shaped lytic lesion progressing ahead of thickened cortex and trabecular bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types
  • Deformation of bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types shape
  • Pseudofractures Pseudofractures A band of bone material of decreased density. Osteomalacia and Rickets (Looser’s lines): small fissures on the convex surface of long bones Long bones Length greater than width. Bones: Structure and Types
  • Protrusio acetabuli Protrusio Acetabuli Marfan Syndrome and iliopectineal line involvement
  • “Ivory spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy”: thickened and enlarged vertebrae 
• Bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types scintigraphy Scintigraphy Sjögren’s Syndrome:
  • Obtain a baseline scan in all cases.
  • Increased uptake at the sites of active lesions
  • May be the earliest imaging change
• Other modalities:
  • Computed tomography (CT) or magnetic resonance imaging (MRI)
  • May be helpful if malignancy Malignancy Hemothorax is suspected
  • Evaluate fractures in selected cases.

Bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma

• Rarely required 
• To rule out malignancy Malignancy Hemothorax 
• Unusual clinical situation (young adult, Asian ethnicity)

Management

Indications for treatment

• Symptomatic disease
• Significant radiologic abnormalities
• Significant biochemical abnormalities

Goals

• Reduce pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways.
• Reduce the rate of bone remodeling Bone remodeling The continuous turnover of bone matrix and mineral that involves first an increase in bone resorption (osteoclastic activity) and later, reactive bone formation (osteoblastic activity). The process of bone remodeling takes place in the adult skeleton at discrete foci. The process ensures the mechanical integrity of the skeleton throughout life and plays an important role in calcium homeostasis. An imbalance in the regulation of bone remodeling’s two contrasting events, bone resorption and bone formation, results in many of the metabolic bone diseases, such as osteoporosis. Bones: Remodeling and Healing.

Pharmacologic treatment

• Bisphosphonates Bisphosphonates Bisphosphonates are pyrophosphate analogs most well-known for treating osteoporosis by preventing bone loss. Bisphosphonates end in the suffix “-dronate” or “-dronic acid” (e.g., alendronate, risedronate, pamidronate) and bind to hydroxyapatite crystals in bone, inhibiting osteoclast-induced bone resorption. Bisphosphonates (first choice— zoledronic acid Zoledronic acid An imidobisphosphonate inhibitor of bone resorption that is used for the treatment of malignancy-related hypercalcemia; osteitis deformans; and osteoporosis. Bisphosphonates):
  • Inhibit osteoclast activity
  • Adverse effects:
    • Gastrointestinal (GI) upset
    • Flu-like symptoms Flu-Like Symptoms Babesia/Babesiosis
    • Musculoskeletal pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
    • Osteonecrosis of the jaw Jaw The jaw is made up of the mandible, which comprises the lower jaw, and the maxilla, which comprises the upper jaw. The mandible articulates with the temporal bone via the temporomandibular joint (TMJ). The 4 muscles of mastication produce the movements of the TMJ to ensure the efficient chewing of food. Jaw and Temporomandibular Joint: Anatomy (especially if invasive dental work done in the prior 6 months)
    • Hypocalcemia Hypocalcemia Hypocalcemia, a serum calcium < 8.5 mg/dL, can result from various conditions. The causes may include hypoparathyroidism, drugs, disorders leading to vitamin D deficiency, and more. Calcium levels are regulated and affected by different elements such as dietary intake, parathyroid hormone (PTH), vitamin D, pH, and albumin. Presentation can range from an asymptomatic (mild deficiency) to a life-threatening condition (acute, significant deficiency). Hypocalcemia
• Calcitonin Calcitonin A peptide hormone that lowers calcium concentration in the blood. In humans, it is released by thyroid cells and acts to decrease the formation and absorptive activity of osteoclasts. Its role in regulating plasma calcium is much greater in children and in certain diseases than in normal adults. Other Antiresorptive Drugs (if bisphosphonates Bisphosphonates Bisphosphonates are pyrophosphate analogs most well-known for treating osteoporosis by preventing bone loss. Bisphosphonates end in the suffix “-dronate” or “-dronic acid” (e.g., alendronate, risedronate, pamidronate) and bind to hydroxyapatite crystals in bone, inhibiting osteoclast-induced bone resorption. Bisphosphonates are not tolerated)

Surgical interventions

• Fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures fixation 
• Resection of bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types tumors
• Non-emergent correction of bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types deformity Deformity Examination of the Upper Limbs
• Joint arthroplasty Arthroplasty Surgical reconstruction of a joint to relieve pain or restore motion. Osteoarthritis
• Spinal decompression: after treatment with bisphosphonates Bisphosphonates Bisphosphonates are pyrophosphate analogs most well-known for treating osteoporosis by preventing bone loss. Bisphosphonates end in the suffix “-dronate” or “-dronic acid” (e.g., alendronate, risedronate, pamidronate) and bind to hydroxyapatite crystals in bone, inhibiting osteoclast-induced bone resorption. Bisphosphonates

Adjunctive measures

• Walking aids AIDS Chronic HIV infection and depletion of CD4 cells eventually results in acquired immunodeficiency syndrome (AIDS), which can be diagnosed by the presence of certain opportunistic diseases called AIDS-defining conditions. These conditions include a wide spectrum of bacterial, viral, fungal, and parasitic infections as well as several malignancies and generalized conditions. HIV Infection and AIDS
• Analgesics
• Physical therapy Physical Therapy Becker Muscular Dystrophy
• Hearing aids AIDS Chronic HIV infection and depletion of CD4 cells eventually results in acquired immunodeficiency syndrome (AIDS), which can be diagnosed by the presence of certain opportunistic diseases called AIDS-defining conditions. These conditions include a wide spectrum of bacterial, viral, fungal, and parasitic infections as well as several malignancies and generalized conditions. HIV Infection and AIDS (if associated with hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss)

Differential Diagnosis

• Metastatic disease: The 5 most common malignancies that metastasize to the bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types are thyroid Thyroid The thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck. Thyroid Gland: Anatomy, lung, breast, kidney, and prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. . Diagnosis is established by history, CT, MRI, and biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma.
• Osteomalacia Osteomalacia Disorder caused by an interruption of the mineralization of organic bone matrix leading to bone softening, bone pain, and weakness. It is the adult form of rickets resulting from disruption of vitamin d; phosphorus; or calcium homeostasis. Osteomalacia and Rickets: marked softening and weakening of bones due to impaired mineralization and most often caused by severe vitamin D deficiency Vitamin D Deficiency A nutritional condition produced by a deficiency of vitamin D in the diet, insufficient production of vitamin D in the skin, inadequate absorption of vitamin D from the diet, or abnormal conversion of vitamin D to its bioactive metabolites. It is manifested clinically as rickets in children and osteomalacia in adults. Fat-soluble Vitamins and their Deficiencies; similar to PDB because of pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways and elevated alkaline phosphatase Alkaline Phosphatase An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. Osteosarcoma, but typical PDB X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests patterns are not seen. Pseudofractures Pseudofractures A band of bone material of decreased density. Osteomalacia and Rickets (Looser’s lines) of osteomalacia Osteomalacia Disorder caused by an interruption of the mineralization of organic bone matrix leading to bone softening, bone pain, and weakness. It is the adult form of rickets resulting from disruption of vitamin d; phosphorus; or calcium homeostasis. Osteomalacia and Rickets occur on the concave, not convex, side of the bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types. 
• Osteosarcoma Osteosarcoma Osteosarcoma is a primary malignant tumor of the bone characterized by the production of osteoid or immature bone by the tumor cells. The disease is most common in children and young adults and most frequently affects growth plates of the long bones, although it can involve any bone. Osteosarcoma: a primary bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types malignancy Malignancy Hemothorax. Occasionally associated with PDB; pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways and soft tissue Soft Tissue Soft Tissue Abscess swelling Swelling Inflammation should prompt an MRI to help in diagnosis. Bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma for confirmation. 
• Giant cell tumor Tumor Inflammation of bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types: benign Benign Fibroadenoma bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types tumors that can be locally aggressive. Associated with increased pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways and swelling Swelling Inflammation. Can occur in association with PDB (usually in the skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull: Anatomy or pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with polyostotic disease); can also arise in non-osseous tissues. Diagnosis is confirmed with MRI and biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma.