Bone & Joint Tumors

Periostal reactions Response to RAPIDLY growing lesions Spiculated "hair-on-end" Onion-skinning

Codman's triangle

Periostal reactions Response to SLOW growing lesions focal cortical thickening

I. Cartilaginous Tumors Osteochondroma Solitary Enchondroma Chondrosarcoma

Osteochondroma Osteocartilaginous exostosis Most common benign tumors or tumorlike lesions of bone, In almost any bone preformed in cartilage, particularly long tubular bones, Presents as a solitary cartilage-capped bony outgrowth protruding from the bone surface near the metaphysis.

The most common location of an osteochondroma is in the region of the knee, particularly the lower metaphysis of the femur or the upper metaphysis of the tibia. occasionally in a flat bone such as a rib, clavicle, ilium, or vertebra.

Pathology A sessile or stalked, cartilage-capped, bony protusion which extends from the metaphysial region Microscopically bony protusion a cap of mature cartilage

bony protusion a cap of mature cartilage

Solitary Enchondroma Central Chondroma Composed of mature hyaline cartilage Develops in the medullary cavity of a single bone Third to sixth decades of life average age : between 30 and 40 years.

The most common location is in the bones of the hand: About one-third of all cases occur in the phalanges. Sometimes: the bones of the foot long tubular bone (the humerus or femur) pelvic bones shoulder girdles.

Radiology: A central, or slightly eccentric, well-circumscribed or "bubbly" radiolucent lesion, finely or densely stippled with calcification.

Pathology: Microscopically, small neoplastic cartilage cells with single small nuclei May form lobules or facets May be partially calcified

- lobules or facets - partially calcified

Enchondromatosis (Ollier’s Disease)

Chondrosarcoma A malignant cartilaginous tumor The third to sixth decades of life (average age of 45 years) Slightly more common in males than females

Chondrosarcoma may originate in the medullary cavity (central chondrosarcoma) about 75% of cases or by malignant transformation of a preexisting enchondroma particularly in patients with enchondromatosis, May originate in a juxtacortical location (peripheral chondrosarcoma) by sarcomatous change in the cartilage cap of an osteochondroma.

Location: flat bones of the pelvis the large limb bones the ribs femur  25% humerus the ribs

Radiology: Radiolucencies (irregular or circular or bubbly) Calcification (granular or lobular radiopaque areas) Destruction of the inner cortex, Enlargement of bone contours, Focal periosteal reaction, Penetration of the cortex.

Chondrosarcoma

Chondrosarcoma

Chondrosarcoma

Microscopy a lobular cartilaginous architecture, highly cellular, more than one nucleated cell per lacuna, occasionally reveals tumor giant cells or clear cells, with increasing grades of malignancy, has marked variation in nuclear and cellular size and shape.

Chondrosarcoma

- Osteoid Osteoma II. Bone-Forming Tumors - Osteoblastoma - Osteogenic Sarcoma

Osteoid Osteoma A distinctive, small (<2 cm), solitary, benign, tumorlike lesion of bone It is composed of osteoid tissue intermixed with woven bone and surrounded by reactive bony sclerosis. Osteoid osteoma most often occurs in children and young adults. A frequent presenting symptom of this condition is night pain, often relieved by aspirin, with localized tenderness in the painful area.

Osteoid osteoma is commonly located in a femur or tibia, Radiology: A representative x-ray picture An osteoid osteoma shows a well circumscribed, small, round or oval, radioluscent or radiodense lesion (the nidus) May be located in or near the cortex and surrounded by densely sclerotic bone.

Osteoid Osteoma

Microscopy The nidus: surrounded by a sclerotic mature bone. narrow trabeculae of osteoid or newly formed bone produced by osteoblasts + vascularized stroma surrounded by a sclerotic mature bone.

Osteoid Osteoma

Osteoblastoma Osteoblastomas are larger (> 2 cm) than osteoid osteomas Mainly osteolytic do not evoke reactive bone sclerosis Higher recurrence rate (~10%) Characterised by immature osteoid production Commonly in the cancellous bone of the spine (posterior elements) and skull

Osteogenic Sarcoma Osteosarcoma: a malignant tumor of bone Most common primary bone tumor after myeloma

In young people under 20 years of age Male / Female : 2/1 Peak beyond 40 years of age: Secondary to preexisting disease Paget's disease (Paget's sarcoma) Previous radiation (irradiation sarcoma) Other conditions

Osteosarcoma may occur in any bone The most frequent location is near the knee (~50-60% of cases) most commonly in the distal end of the femur the upper end of the tibia, upper end of the humerus, pelvis, upper end of the femur. Bone-forming cells produce alkaline phosphatase The serum alkaline phosphatase is markedly elevated in many patients with osteosarcoma.

Radiology of a long bone usually show a large, ill-defined tumor. The bone-producing (osteoblastic) lesion is located in the medulla near the metaphysis Lifts up the periosteum (periostal reaction) often producing "Codman's triangle", an angle between the outer cortex and the elevated periosteum, Sun-rays pattern Less common : destructive (osteolytic) lesions with a "moth eaten" appearance of the cortex.

Osteosarcoma

Osteosarcoma Osteosarcoma

Osteosarcoma

Osteosarcoma: Lung mets

Microscopy Proliferating malignant spindle- cell stroma Osteoid or immature bone

Osteosarcoma

Osteosarcoma

III. Tumors of Other or Unknown Histogenesis Ewing’s sarcoma Giant Cell Tumor

Ewing's Sarcoma A malignant, small, round-cell tumor of bone Composed of uniform, densely packed, tumor cells with round nuclei and indistinct cellular borders The histogenesis of Ewing's sarcoma remains controversial

The most common presenting symptom of Ewing's sarcoma is bone pain, Mainly in children second decade of life average age of 13-14 years Male/Female : 2/1 The most common presenting symptom of Ewing's sarcoma is bone pain, swelling, tenderness, and heat in the affected part, slight fever, and elevated erythrocyte sedimentation rate, which all together may mimic osteomyelitis.

Ewing's sarcoma may occur in any bone but most frequently involves long bones. Femur (27%), pelvic bones (18%), tibia and fibula (17%), humerus (10%), scapula (6%). Radiology: A mottled "moth eaten" destructive lesion in the diaphysis periosteal reactive new bone sometimes formed in concentric layers and producing an "onion skin" appearance, and often accompanied by a soft-tissue mass.

Ewing's sarcoma

Microscopically, uniform, densely packed, tumor cells with a single, round or oval nucleus, indistinct cellular borders, and a size and appearance somewhat resembling lymphocytes (small round blue cells). The tumor cell cytoplasm characteristically contains PAS-positive glycogen granules. The tumor cells grow in sheets, sometimes with central necrosis, but without pattern, such as the rosettes typically formed by metastatic neuroblastoma.

Giant Cell Tumor An aggressive benign tumor Composed of : well vascularized stroma plump, spindly, and oval tumor cells multinucleated tumor giant cells Over the age of 20: most commonly in the third decade of life slight female preponderance

The skeletal location: 50% of cases occur near the knee most commonly in the distal end of the femur or the upper end of the tibia. The x-ray picture : Large, eccentric, oval, Radioluscent destructive lesion centered in the epiphysis, Cortical erosion and thinning, Expanding the bone contours without a border.

Giant Cell Tumor

Giant Cell Tumor

1. plump, spindly, and oval stromal cells Microscopy: 1. plump, spindly, and oval stromal cells 2. multinucleated tumor giant cells which are formed by fusion of the stromal cells Differential diagnosis: reparative granulomas brown tumors of hyperparathyroidism the lytic phase of Paget's disease aneurysmal bone cyst

IV. Miscellaneous Tumors and Tumor-like Lesions of Bone Multiple Myeloma Chordoma Myositis Ossificans

Multiple Myeloma Multiple myeloma is a malignant tumor of plasma cells Characterized by multiple lytic destructive lesions of bone, immunoglobulin abnormalities (monoclonal gammopathy), bone marrow failure, recurrent infections, hypercalcemia, amyloid deposits, renal insufficiency.

Over 40 years of age and with an average age of 60 years. Multiple myeloma most often involves the vertebral column, ribs, and skull although virtually any, or all, bones can be affected. The most common symptom is bone pain, Other symptoms bone marrow failure (anemia, bleeding), recurrent infections, serum hyperviscosity, hypercalcemia, renal failure of multifactorial pathogenesis (myeloma nephropathy, associated amyloidosis, nephrocalcinosis).

Radiology: Skull, ribs, or other affected bones Multiple lytic "punched out" lesions. Osteopenia/Osteoporosis

Multiple Myeloma

Microscopy: Bone marrow. Plasma cell tumor: an eccentric, round, hyperchromatic nucleus sometimes with a "cartwheel" distribution of chromatin frequent double or triple nuclei, abundance of cytoplasm with a purple (basophilic) color and an occasional perinuclear "halo", distinct cell borders.

Multiple Myeloma

Chordoma A malignant tumor of the notochord Arises towards either end of the vertebral column, most often in the sacrococcygeal region but also in the spheno-occipital region. Fifth to eighth decades of life, average age : 50 years slight female preponderance.

Clinical x-rays : Pathology large soft tissue mass lytic destruction of the sacrococcygeal bone. Pathology Grossly, large, soft, lobulated, gelatinous tumor extends from the sacrum and expanding into the pelvic cavity. Microscopically, large and vacuolated, so-called physaliferous (bubbly/drop-like) cells.

Chordoma

Myositis Ossificans A nonneoplastic tumor-like lesion Trauma to skeletal muscle  hemorrhage  distrophic calcification  heterotropic ossification It must be distinguished from extraosseous osteogenic sarcoma. Clinical x-rays: peripherally calcifying (ossifying) lesion located in the soft tissues or next to bone.

Microscopically, newly formed bone matures toward the periphery of the lesion, whereas the center or interior of the lesion is cellular and poorly differentiated. The presence of peripheral maturity and central immaturity of the lesion is called "zoning phenomenon" and is characteristic of myositis ossificans but lacking in osteogenic sarcoma.

Myositis Ossificans

Joint Tumors Synovial tumors Benign tumors Malignant tumors Tenosynovial giant cell tumor Localized tenosynovial giant cell tumor Diffuse tenosynovial giant cell tumor (extraarticular pigmented villonodular synovitis, florid tenosynovitis) Malignant tumors Synovial sarcoma Biphasic (fibrous and epithelial) synovial sarcoma Monophasic (fibrous or epithelial) synovial sarcoma Malignant giant cell tumor of tendon sheath

Misdiagnose  benign tumor 8-10% of all sarcomas All ages Location: extremities especially the lower extremities around the knees Misdiagnose  benign tumor small size, slow growth, and well-defined appearance

Synovial sarcoma in the anterior left upper thigh and/or inguinal region