Mushroom-shaped bony outgrowths that develop at the margins of the articular surface.
Lipoma, a benign tumor of fat.
Any cancer can spread to the bone, but typically multifocal metastases are common. Kidney and thyroid cancers may be solitary. Most involve the axial skeleton.
Rearrangements of 17p13, leading to USP6 fusion.
In the medullary cavity, invading the cortex, periosteum, and soft tissue.
Localized developmental arrest where all components of normal bone are present but do not differentiate into mature structures.
Multiloculated blood-filled cystic spaces.
Metaphyseal fibrous defects.
Dislodged pieces of cartilage that tumble into the joint, forming loose bodies.
Liposarcoma is one of the most common sarcomas of adulthood, with key genetic markers including amplification of 12q13-q25 and t(12;16).
Rhabdomyosarcoma.
25% to 65%.
Parvovirus B19, Rubella, EBV, Hepatitis B and C.
They are cleaved, yielding fissures and clefts.
Hips, knees, lower lumbar, cervical, PIP, DIP, 1st carpometacarpal, and 1st tarsometatarsal joints.
CD4+ T cells.
In the soft tissues near the knee joint.
Patients with sickle cell disease.
M. tuberculosis.
Characteristic radiologic findings, sterile turbid synovial fluid with decreased viscosity, poor mucin clot, inclusion-bearing neutrophils, and a combination of RF and CCP antibodies.
Men in their 20s or 30s.
HLA B27 and HLA-Cw6.
The synovium becomes edematous and congested.
Repetitive precipitation of MSU, encrustation of the articular surface, hyperplastic and fibrotic synovium, pannus formation, and juxta-articular bone erosion.
Mazabraud Syndrome.
Palmar (Dupuytren Contracture), Plantar, and Penile (Peyronie disease).
TNF stimulates synovial cells to secrete proteases that destroy hyaline cartilage and is firmly implicated in the pathogenesis of RA.
By detecting anti-Borrelia antibodies.
Patients with severe erosive disease, rheumatoid nodules, and high titers of RF.
Men are affected three times more often than women.
Simple excision.
Gastrointestinal infections by Yersinia, Salmonella, Shigella, and Campylobacter.
5-6 cm.
Asymptomatic Hyperuricemia, Acute Arthritis, Asymptomatic Intercritical Period, and Chronic Tophaceous Gout.
Occurs equally in boys and girls, early adolescence. Stops enlarging at time of growth plate closure. Commonly affects femur, tibia, ribs, jawbones, calvarium, humerus. Asymptomatic, often an incidental finding. Shows ground-glass appearance with well-defined margination.
Prominent osteophytes at the DIP joints, more common in women.
Also called degenerative joint disease, it is the degeneration of cartilage resulting in structural and functional failure of synovial joints. It is the most common type of joint disease and is considered an intrinsic disease of the cartilage where chondrocytes respond to biochemical and mechanical stress.
Borrelia burgdorferi transmitted by deer tick (Ixodes).
Conventional, clear cell, dedifferentiated, and mesenchymal.
Wide surgical excision.
Multinucleated osteoclast-type giant cells.
A small cyst located near a joint capsule or tendon sheath, arising from cystic or myxoid degeneration of connective tissue.
In the deep dermis, subcutis, or muscle.
Direct extension, lymphatic or hematogenous spread, and intraspinal seeding via Batson plexus of veins.
A mass of edematous synovium, inflammatory cells, granulation tissue, and fibroblasts that grow over the articular cartilage and cause its erosion.
Age (20-30 y/o), genetic predisposition (HGPRT, multifactorial inheritance), heavy alcohol consumption, obesity, drugs (Thiazides), and lead toxicity (Saturnine Gout).
Malaise, fatigue, and generalized pain.
90%.
Ankles, knees, and feet in an asymmetric pattern.
The resolubilization of crystals after the episode of crystallization abates.
The presence of MSU or tophi in the renal medullary interstitium or tubules, leading to uric acid nephrolithiasis and pyelonephritis.
Occurs slightly earlier than monostotic fibrous dysplasia. Commonly affects femur, skull, tibia, humerus, ribs, fibula, radius, ulna, mandible, vertebra. Craniofacial involvement in 50% of those with moderate number of bones affected, 100% in extensive skeletal disease.
Genetic and environmental factors.
The uterus.
Swollen joint with restricted range of motion, fever, leukocytosis, and elevated ESR.
Small joints, generally symmetrically.
Osteochondroma.
More than 80%.
Between the 30s to 50s.
Underlying epiphyseal osteomyelitis.
Somatic gain-of-function mutation in the GNAS1 gene.
MYH9-USP6 fusion gene (t(17;22)).
Deep achy pain that worsens with use, morning stiffness, crepitus, and limitation of range of motion.
Mutations in APC or β-catenin.
Aging and biomechanical stress. OA prevalence increases beyond age 50.
Presence of 4 of the following: Morning stiffness, arthritis in 3 or more joints, arthritis of hand joints, symmetric arthritis, rheumatoid nodules, serum RF, and typical radiologic findings.
A heterogeneous group of disorders of unknown cause that present with arthritis before age 16 and persist for at least 6 weeks.
Conventional chondrosarcoma.
A malignant bone tumor characterized by primitive round cells without obvious differentiation.
Characterized by skeletal features of polyostotic fibrous dysplasia with multiple deformities and intramuscular myxomas in adults. Although benign, it may cause local compression symptoms.
May appear as purely lytic, purely blastic, or mixed lesions. Prostatic adenocarcinoma is predominantly blastic, while kidney, lung, GIT, and melanoma typically present as lytic lesions.
SS18-SSX1,2,4 gene translocation.
Chronic progressive monoarticular infection with insidious, gradual progressive pain and formation of granulomas with central casseous necrosis.
Hyperuricemia is plasma levels above 6.8 mg/dl and is necessary but not sufficient for the development of gout.
Radial elevation of the wrist, ulnar deviation of fingers, and flexion-hyperextension of fingers (Swan-Neck, Boutonniere deformity).
Pathologic changes in ligamentous attachments, involvement of sacroiliac joints, absence of RF, and association with HLA-B27.
Enzymes that synthesize heparin sulfate.
They stop growing.
In the axial skeleton.
6% to 10%.
The presence of Homer-Wright Rosettes.
Tophi, which are large aggregations of urate crystals surrounded by an intense inflammatory reaction of foreign body giant cells.
Chondrocytes eventually die and are sloughed off.
Characterized by precocious sexual development, most often in girls, and includes endocrinopathies such as hyperthyroidism, pituitary adenoma (GH secreting), and primary adrenal hyperplasia. Often unilateral with ipsilateral skin pigmentation. Cutaneous macules are large, dark to café au lait color with irregular serpiginous borders on neck, chest, back, shoulder, and pelvic region.
Alveolar, Embryonal, and Pleomorphic.
Gonococcal arthritis.
Marked by synoviocyte hyperplasia, fibrin deposition, mononuclear infiltrates, and onion skin thickening of arterial walls.
Transient attacks of acute arthritis initiated by crystallization of monosodium urate within and around the joints.
Baker cysts are herniations of the synovium that develop in the posterior knee due to increased intra-articular pressure.
During childhood.
Sessile or pedunculated, 1-20 cm, with a cap composed of benign hyaline cartilage of varying thickness.
2nd to 3rd decades of life.
An autoimmune reaction initiated by a prior infection.
The peripheral joints of the hands and feet, with the DIP joints first affected in an asymmetric distribution.
Destructive lytic tumor with permeative margins that extends into the surrounding soft tissues.
75%, with a long-term cure rate of 50%.
Well circumscribed, intramedullary, vary in size. Larger lesions expand and distort the bone. Tan-white, gritty composed of curvilinear trabeculae of woven bone surrounded by moderately cellular fibroblastic proliferation. Mimics Chinese characters. Bone lacks prominent osteoblastic rimming. Nodules of hyaline cartilage of disorganized growth plate. Cystic degeneration, hemorrhage, foamy macrophages.
Large, infiltrative masses that recur but do not metastasize.
1. Chondrocyte injury due to genetic and biochemical factors. 2. Early OA where chondrocytes proliferate and secrete mediators to remodel the cartilaginous matrix. 3. Late OA characterized by repetitive injury and chronic inflammation leading to chondrocyte dropout, marked loss of cartilage, and extensive subchondral bone changes.
S. aureus.
Endogenous (monosodium urate, calcium pyrophosphate dehydrate, basic calcium phosphate) and Exogenous (steroid ester crystals, talcum, biomaterials polyethylene, and methyl methacrylate).
Purpura, cutaneous ulcers, and nail bed infarction.
85%.
TH1 and TH17 cell mediators.
Men are affected twice as frequently as women.
Pencil in a cup deformity.
20s to 40s.
Pseudogout, also known as chondrocalcinosis, is caused by CPPD deposition and occurs in older patients.
Less than 5 cm, circumscribed, slightly infiltrative.
In the retroperitoneum, thigh, knees, and distal extremities.
Eosinophilic spindle cells with blunt-ended hyperchromatic nuclei arranged in interweaving fascicles.
Gonococcus.
Joint aspiration.
Dense neutrophilic infiltrates that permeate the synovium and monosodium urate crystals found in the cytoplasm of neutrophils.
Multiple hereditary exostosis syndrome.
In their 40s or older.
A group that includes Ewing Sarcoma and Primitive Neuroectodermal Tumor (PNET).
A tumor that develops in the lining of joints, tendon sheaths, and bursae, and can be diffuse or localized.
A chronic inflammatory disorder of autoimmune origin that principally attacks the joints.
Sarcoma botyroides.
Complement (C5, C6, C7) deficiency.
Acute Arthritis, Chronic Tophaceous arthritis, Tophi in various sites, and Gouty nephropathy.
HLA and PTPN22, similar to RA.
Associated with germline loss of function in EXT1 or EXT2 genes.
Calcified matrix appears as foci of flocculent densities.
(11;22)(q24;q12) translocation, fusing EWS and FLI1.
A self-limited fibroblastic and myofibroblastic proliferation that occurs in young adults, often with a history of trauma.
Serum IgM or IgA that bind to Fc portions of their own IgG, often depositing in the joints as immune complexes.
In late adolescence and early adulthood.
A condition characterized by the destruction of articular cartilage and bony ankylosis, especially in the sacroiliac and apophyseal joints.
Arthritis, non-gonococcal urethritis or cervicitis, and conjunctivitis.
A chronic inflammatory arthropathy associated with psoriasis that affects the peripheral and axial joints and entheses.
Via hematogenous spread from distant sites.
Firm, non-tender, round-oval nodules arising from subcutaneous tissue, resembling necrotizing granulomas.
H. influenza arthritis.
The knee.
Joint effusion, juxta-articular osteopenia with erosions, narrowing of joint spaces, and loss of articular cartilage.
Oligoarthritis is more common, systemic disease is more frequent, large joints are more affected than small joints, rheumatoid nodules and factors are usually absent, and ANA is common.
In bones of endochondral origin, arising from the metaphysis near the growth plate of long tubular bones.
About a year, and it generally clears.
To relieve pain and inflammation and to slow or arrest joint destruction.
A malignant tumor that produces cartilage.
Most are grade 1 with a 5-year survival rate of 80-90%, rarely metastasize.
Younger than 20 years old.
