Bone&Joints برای بزرگنمایی عکسها کلیک را روی ان نگه دارید..... Figure 40.1 A, Coronal-plane MRI shows a diffuse infiltrate of variable signal intensity in the proximal tibia with adjacent soft tissue edema. B, In acute osteomyelitis, the inflammatory infiltrate consists primarily of neutrophils, and necrotic bone is resorbed by osteoclasts Figure 40.2 Two Examples of Chronic Osteomyelitis Involving the Fibula. A, Dense, irregular bone is evident. B, Prominent periosteal bone formation may cause confusion with a primary bone tumor. C, In chronic osteomyelitis, there is extensive fibrosis of the marrow space and a chronic inflammatory infiltrate Figure 40.3 Gummatous involvement of tibia in a 45-year-old woman Figure 40.4 Bone necrosis is characterized by loss of osteocytes and necrosis or fibrosis of the fatty marrow Figure 40.5 AP (A) and lateral (B) radiographs show a large metadiaphyseal bone infarct of femur. The irregular area of increased radiodensity is indicative of new bone production superimposed on necrosis. (Courtesy of Dr H Danziger, Welland, Ontario, Canada) Figure 40.6 A, Coronal CT shows a discrete area of subchondral density with cystic change, indicative of avascular necrosis. B, A discrete area of avascular necrosis, which appears yellowish on cut section. Separation of the articular cartilage and subchondral bone is characteristic. C, The infarct is contained by a hypervascular reactive zone. The separation of the articular cartilage and subchondral bone is evident histologically Figure 40.7 Sharply delimited area of osteochondritis dissecans of medial condyle (arrow). This was easily enucleated Figure 40.8 Radiograph of Paget disease involving the tibia. Both cortical thickening and coarsening of the cancellous bone is accompanied by an anterior bowing deformity Figure 40.9 Paget disease involving the femoral head. There is marked deformity of the femoral head with coarsening of the bone, as well as secondary osteoarthritis Figure 40.10 Paget Disease. A, Early changes. There is prominent osteoclastic activity, osteoblastic activity, and fibrosis. B, A well-established case, with thick, irregularly shaped bone trabeculae and cracking artifact along reversal lines Figure 40.11 Sino-Nasal Osteoma With Osteoblastoma-Like Foci. A, CT scan shows a lobulated, radiodense mass. The less dense, central area has osteoblastoma-like features. B, Portion of the mass resembling cortical bone. C, Osteoblastoma-like focus, consisting of woven bone with prominent osteoblasts and osteoclasts Figure 40.12 AP radiograph of an osteoid osteoma of the tibia. The radiolucent central nidus is surrounded by dense, reactive bone Figure 40.13 Osteoid Osteoma. A, Grossly, the gritty 8-mm nidus of the osteoid osteoma is evident within dense bone. B, Medium-power and C, high-power microscopic views of osteoid osteoma. There is woven bone surrounded by plump osteoblasts. The stroma is cellular and well vascularized Figure 40.14 Osteoblastoma of the Spine. A, CT scan shows a well-circumscribed radiolucent lesion with central density arising in the posterior elements of the vertebra. Reactive bone formation is evident in the vertebral body adjacent to the lesion. B, Low-power view shows a sharply circumscribed border. C, Woven bone with prominent osteoblasts, fibrovascular stroma, and ectatic blood vessels characterize osteoblastoma Figure 40.15 Radiographic Features of Conventional Osteosarcoma of the Distal Femur. A, Radiograph, B, coronal CT, and C, coronal MRI show a highly destructive bone-forming mass arising in the metaphysis and involving adjacent soft tissue Figure 40.16 Gross appearance of osteosarcoma of the A, distal femur, B, proximal humerus, and C, distal femur. All three lesions extend into soft tissue and cause elevation of the periosteum Figure 40.17 Main Histologic Variants of Conventional Osteosarcoma. A, Osteoblastic osteosarcoma. B, Chondroblastic osteosarcoma. C, High-grade fibroblastic osteosarcoma. In each instance, osteoid deposition is identified. D, Microscopic appearance of osteosarcoma showing characteristic basophilic osteoid with an appearance that is reminiscent of fungal hyphae Figure 40.18 Telangiectatic Osteo- sarcoma. A, Grossly, the tumor is hemorrhagic and causes bone destruc- tion with involvement of soft tissue. B, Microscopically, the thin strips of tissue from telangiectatic osteosarcoma mimic aneurysmal bone cyst. C, At high power, telangiectatic osteosarcomas show marked cytologic atypia and mitotic activity Figure 40.19 Gross appearance of low-grade central osteosarcoma of the tibia. (Courtesy of Dr Juan José Segura, San José, Costa Rica) Figure 40.20 Parosteal Osteosarcoma. A, On lateral plain radiograph and B, lateral CT scan, a lobulated, dense mass arises from the surface of the posterior femoral metaphysis and encompasses the bone. C, The gross appearance of the lesion closely reflects its radiographic features Figure 40.21 Parosteal Osteosarcoma. A, Mildly atypical spindle cells grow between irregularly shaped woven bone trabeculae. B, An immu- nostain for MDM2 is positive in the majority of the spindled cells in parosteal osteosarcoma Figure 40.22 A, MRI and B, gross features of periosteal osteosarcoma. The lesion arises from the surface of the proximal femoral metadiaphysis, and the cut surface is cartilaginous and contains reactive bone oriented perpendicular to the femoral surface Figure 40.23 A, CT and B, gross features of osteosarcoma of the jaw. C, Most gnathic osteosarcomas are of the chondroblastic variety Figure 40.24 When treated with neoadjuvant chemotherapy, susceptible osteosarcomas show dropout of viable tumor cells ("necrosis"), but the osteoid matrix persists Figure 40.25 A, Coronal-plane CT shows a circumscribed metaphyseal enchondroma with stippled calcifications. B, Histologically, enchondromas are composed of lobules of mature hyaline cartilage which are partially or complete encompassed by bone Figure 40.26 A, Arm of a patient affected by Maffucci syndrome. Innumerable chondromas are seen concentrated in the distal aspect of the extremity, and calcified phleboliths indicate hemangiomas in the soft tissue. B, Above-knee amputation specimen from a patient with Maffucci syndrome who developed a chondrosarcoma of the distal femur. Nodules of enchondroma can also be seen in the tibial and fibular stumps Figure 40.27 A, Radiographic and B, CT features of periosteal chondroma. This small, surface-based cartilage lesion is often partially covered by reactive bone from the overlying periosteum, and causes erosion of the underlying cortex. C, Periosteal chondromas are composed of mature hyaline cartilage and covered by periosteum Figure 40.28 A, Radiograph showing a pedunculated osteochondroma arising from the distal femoral metaphysis and pointing away from the knee joint. B, Grossly, this osteochondroma was covered by only a thin cartilage cap and was complicated by the formation of a bursa Figure 40.29 A and B, Gross and whole-mount appearance of osteochondroma. Mature bone is covered by a well-differentiated cartilaginous cap Figure 40.30 Chondroblastoma. A, Lateral radiograph of the knee shows a well-circumscribed radiolucent lesion arising in the epiphysis. B, MRI shows the circumscribed chondroblastoma with intense surrounding edema, a characteristic imaging feature. C, On low magnification, chondroblastomas are composed of islands of immature cartilage, mononuclear chondroblasts, and multinucleated giant cells. D, Chondroblasts have characteristic features, including well-defined cytoplasmic borders and longitudinal nuclear grooves Figure 40.31 Radiograph of chondromyxoid fibroma, which appears as a well-defined metaphyseal radiolucency with surrounding reactive bone. The overlying cortex may be absent in larger lesions Figure 40.32 Microscopic appearance of chondromyxoid fibroma. Peripheral hypercellularity is common, and giant cells are encountered at the periphery of lobules Figure 40.33 A, Radiographic and B, gross appearance of central chondrosarcoma. The lesion consists of gray hyaline cartilage which causes deep endosteal scalloping accompanied by cortical thickening Figure 40.34 A, CT, B, MRI, and C, gross appearance of a secondary peripheral chondrosarcoma arising from an osteochondroma of the scapula. The cartilage cap is thick and highly irregular, and the lesion surrounds the scapula Figure 40.35 Microscopic features of A, grade 1, B, grade 2, and C, grade 3 chondrosarcoma Figure 40.36 Clear Cell Chondrosarcoma. A, CT shows a deceptively circumscribed epiphyseal lesion, suggesting the possibility of a benign lesion. B, On low magnification, clear cell chondrosarcomas often contain large areas of woven bone and numerous multinucleated giant cells. C, The defining cells are large and contain either eosinophilic or clear cytoplasm, large nuclei, and a prominent central nucleolus Figure 40.37 A, Gross and B, microscopic features of dedifferentiated chondrosarcoma. The low-grade chondroid component can be seen in the medullary cavity, and the high-grade component is present in the soft tissue Figure 40.38 A, Gross photograph of a mesenchymal chondrosarcoma involving the bones of the midfoot. B, Mesenchymal chondrosarcomas contain areas of immature cartilage that alternate with primitive, round cell foci with prominent branching blood vessels Figure 40.39 Radiographic Features of Giant Cell Tumor. A, Radiograph, B, MRI. Giant cell tumors involve the epiphysis and metaphysis of skeletally mature patients Figure 40.40 Gross Appearance of Giant Cell Tumor of Bone. This tumor can vary from red-brown and hemorrhagic, as in this example in the proximal tibia complicated by a pathologic fracture (A), to yellow, as seen in this lesion in the fibula (B). C, Giant cell tumor can aggressively destroy bone and involve soft tissue Figure 40.41 Giant Cell Tumor. A, The "typical" giant cell tumor contains numerous giant cells arranged diffusely and evenly, with mononuclear stromal cells in between. B, Some lesions may contain prominent fibrous or fibrohistiocytic areas devoid of giant cells Figure 40.42 Ewing Sarcoma of the Clavicle. A and B, CT and MRI show an aggressive lesion with associated periosteal reaction. C, The resection specimen shows enlargement of the clavicle, but the tumor is extensively necrotic following neoadjuvant chemotherapy Figure 40.43 Microscopic Features of Ewing Sarcoma. A and B, Sheets of primitive, small, round cells are separated by fibrous septa. C, Some lesions contain rosettes. D, Ewing sarcoma shows strong immunoreactivity for CD99 in a membranous pattern Figure 40.44 A, Malignant lymphoma involving the distal femur associated with bone destruction and bone production. These lesions may be erroneously diagnosed as chronic osteomyelitis. B, The tumor is of large cell type and is associated with some fibrosis Figure 40.45 Vertebral Hemangioma. A, CT scan showing the typical corduroy pattern associated with hemangiomas in this site. B, Histologic features of a cavernous hemangioma of bone Figure 40.46 Epithelioid Hemangioma of Bone. A, Epithelioid hem- angioma is composed of well-formed vessels lined by prominent epithelioid endothelial cells. The vessels are separated by an inflammatory infiltrate rich in eosinophils. B, An immunostain for ERG highlights the endothelial cells Figure 40.47 Gross appearance of multicentric epithelioid hemangio- endothelioma involving femur and tibia Figure 40.48 A and B, Microscopic appearance of epithelioid heman- gioendothelioma of bone. Cords and nests of epithelioid endothelial cells are deposited in a prominent matrix. Occasional tumor cells contain intracytoplasmic vacuoles or blisters Figure 40.49 Angiosarcoma of Bone. A, Highly atypical endothelial cells line irregular vascular spaces. B, Tumor cells are strongly positive for ERG Figure 40.50 Desmoplastic Fibroma. A, CT highlights a large, destructive mass arising in the jaw. B and C, Desmoplastic fibroma is poorly circumscribed and composed of fascicles of bland fibroblasts, similar to soft tissue fibromatosis Figure 40.51 A, An infarct-associated undifferentiated pleomorphic sarcoma of the proximal humerus. The serpiginous infarct appears yellowish and calcified, while the sarcoma is gray and fleshy. B, Undifferentiated pleomorphic sarcoma of bone is histologically identical to its soft tissue counterpart Figure 40.52 Sacral Chordoma. A, T1- and B, T2-weighted MRI shows the chordoma destroying the distal sacrum and involving anterior soft tissue. C, The gross appearance of chordoma is lobulated and gelatinous. D and E, Chordomas are lobulated and composed of cords and nests of epithelioid cells deposited in a myxoid stroma. Individual tumor cells may contain cytoplasmic vacuoles. F, An immunostain for brachyury confirms the diagnosis of chordoma Figure 40.53 Microscopic Patterns of Adamantinoma. A, Basaloid, B, Tubular, C, Squamoid, and D, Spindled Figure 40.54 Ill-defined lytic lesion in midshaft of fibula produced by metastasis of lung carcinoma Figure 40.55 Radiograph of a metastatic pulmonary carcinoma involving the metacarpal Figure 40.56 A, Gross appearance of femur with medullary involvement by metastatic renal cell carcinoma. B, Microscopic appearance. The optically clear appearance of the cytoplasm and the extensive hemorrhage are characteristic features Figure 40.57 Typical solitary bone cyst of upper end of humerus abutting against epiphyseal plate in a 13-year-old boy Figure 40.58 Gross appearance of solitary bone cyst. A large lesion located in the upper metaphysis of the humerus Figure 40.59 Microscopically, unicameral bone cyst contains a fibrous wall with adherent fibrin-like material that may incorporate into the wall Figure 40.60 Radiographic Features of Aneurysmal Bone Cyst. A, Radiograph, B, MRI. Prominent fluid-fluid levels are seen on MRI Figure 40.61 Gross appearance of an aneurysmal bone cyst, which contains multiple blood-filled cystic structures Figure 40.62 Microscopic Features of Aneurysmal Bone Cyst. A, Multiple blood lakes are surrounded by a giant cell-rich fibroblastic proliferation. B, Amorphous, calcified material is commonly identified in the walls of aneurysmal bone cyst and is a diagnostically useful finding Figure 40.63 MRI shows a well-circumscribed intraosseous ganglion cyst of the medial malleolus of the ankle Figure 40.64 Radiograph of a non-ossifying fibroma. This radiolucent lesion arises in the metaphysis of the distal tibial cortex and is surrounded by prominent reactive bone Figure 40.65 Non-ossifying fibromas are composed of bland spindled cells, often arranged in a vague storiform pattern, and contain scattered giant cells Figure 40.66 Fibrous Dysplasia. This lesion, located in the femoral neck, is well defined, radiolucent, and surrounded by reactive bone. A pathologic fracture extends through the lesion Figure 40.67 Gross appearance of fibrous dysplasia of the rib. The lesion forms a fusiform, expanded mass that is grayish white Figure 40.68 Histologic Features of Fibrous Dysplasia. A, Irregularly shaped woven bone spicules are surrounded by fibrous stroma. The surfaces of the trabeculae are devoid of osteoblasts. B, Chondroid nodules may be prominent Figure 40.69 Osteofibrous Dysplasia. A, Osteoblastic rimming is a prominent feature of osteofibrous dysplasia. B, Individual keratin-positive spindled stromal cells are seen, but nests of epithelial cells are absent Figure 40.70 Langerhans Cell Histiocytosis. A, Punched out lesion of the skull. B, Histologic features of Langerhans cell histiocytosis include large, ovoid Langerhans cells with surrounding inflammation rich in eosinophils. C, An immunostain for CD1a highlights Langerhans cells Figure 40.71 Rosai-Dorfman Disease. A, Large histiocytes admixed with acute and chronic inflammatory cells. The histiocytes engulf other inflammatory cells ("emperipolesis"). B, The histiocytes in Rosai-Dorfman disease are strongly immunoreactive for S-100 protein Figure 40.72 Gross appearance of ganglion cyst. (Courtesy of Dr RA Cooke, Brisbane, Australia; from Cooke RA, Stewart B. Colour Atlas of Anatomical Pathology. Edinburgh: Churchill Livingstone; 2004) Figure 40.73 Microscopic appearance of ganglion cyst. The wall is composed of dense fibrous tissue, and there is no synovial lining Figure 40.74 Gross appearance of prepatellar bursa with chronic inflammation Figure 40.75 Gross appearance of Baker cyst Figure 40.76 Advanced osteoarthritis of femoral head: A, gross appear- ance, showing near-total disappearance of articular cartilage; B, whole mount of the same case Figure 40.77 Early changes in osteoarthritis include cracking of the articular cartilage and cloning of chondrocytes (A). B, Later, the cartilage is completely eroded, resulting in thickened subchondral bone Figure 40.78 Neuropathic changes in wrist secondary to syringomyelia Figure 40.79 Synovial hyperplasia and heavy lymphoplasmacytic infiltrate in rheumatoid arthritis Figure 40.80 Examination of the bone in rheumatoid arthritis shows destruction of the articular surface by pannus, as well as lymphoid aggregates in the subchondral bone Figure 40.81 Rheumatoid nodule with early cystic change of the "necrobiotic" center. Note the peripheral palisading of histiocytes Figure 40.82 Gout. A, Gross appearance of large gouty deposit in the posterior knee. B, A lesion of periarticular gout showing a foreign body-type giant cell reaction to the deposited crystals. The crystalline nature of this material is not obvious in this formalin-fixed specimen Figure 40.83 Aggregates of calcium pyrophosphate crystals appear bluish and lack a significant inflammatory response. Examination with polarized light will highlight the typical diamond or rhomboid shape of the crystals Figure 40.84 Periprosthetic joint infection. Tissue beneath the fibrin surface showing marked acute inflammation (greater than five neutrophils in five high-power fields, suggesting infection) Figure 40.85 A, Gross appearance of tenosynovial giant cell tumor. The lesion is small, well circumscribed, solid, and with a brownish cast. B, Whole-mount appearance of the cross section of a lesion located in the finger. Note the lobulated quality Figure 40.86 Microscopic appearance of tenosynovial giant cell tumor. A polymorphic infiltrate of small histiocytes and multinucleated giant cells is embedded in dense fibrous tissue Figure 40.87 Pigmented Villonodular Synovitis. A, The villous architecture is evident on the surface of the lesion. B, Giant cells and histiocyte-like cells contain rings of iron in their cytoplasm. C, Foamy histiocytes may be prominent. D, Hyalinization may be striking Figure 40.88 A, Synovial chondromatosis. Nodules can be seen clearly in the joint space on radiographic examination. B, Microscopically, the chondrocytes in synovial chondromatosis maintain a characteristic nested appearance
