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Musculoskeletal system. SYLLABUS: RBP( Robbins Basic Pathology ) Chapters : The Musculoskeletal System. Musculoskeletal system. 56 Chondroma 57 Chondrosarcoma 58 Osteoma 60 Ostosarcoma 187 Aneurysmal bone cyst 189 Eosinophilic granuloma. Chondroma.
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Musculoskeletal system SYLLABUS: RBP(Robbins Basic Pathology) Chapters: TheMusculoskeletal System
Musculoskeletal system 56 Chondroma 57 Chondrosarcoma 58 Osteoma 60 Ostosarcoma 187 Aneurysmal bone cyst 189 Eosinophilic granuloma
Chondroma - well circumscribed nodules of cartilage - hyaline matrix - cytologically benign neoplastic chondrocytes residing in lacunae
Chondrosarcoma - sheets or ill-defined nodules of cartilage with variable nuclear atypia (enlarged, pleomorphic, hyperchromatic nuclei) - sometimes two or more nuclei per lacuna - invasion of trabecular bone - soft tissue lesions usually with abundant myxoid stroma or spindle cells
Osteoma -dense, mature, lamellar bone
Ostosarcoma - minimal diagnostic requirement is malignant calcified osteoid - cytologic malignant features include enlarged, hyperchromatic, pleomorphic, mitotically active nuclei, possibly atypical mitoses - architecture extremely variable: - sheets of osteoid with osteoblast lacunae and little fibrous stroma - thin osteoid trabeculae and more stroma - rare foci of osteoid in irregular islands or rosettes - may have cartilage, and giant cells
Aneurysmal bone cyst (ABC) Probably rather a degenerative change that can occur in many lesions than an independent lesion. About half of cases have areas of precursor lesion (wide variety). - multiple blood filled lakes - fibrous and bony septa - many giant cells often in a row beneath the surface - no cytologic atypia - foci of osteoid and bone
Eosinophilic granuloma (Langerhans' cell histiocytosis of bone, Histiocytosis X) - a variety of cell types, but only Langerhans' cell is diagnostic - number of Langerhans' cells present is variable - prototypical Langerhans' cells have abundant, powdery, eosinophilic cytoplasm and characteristic bean-shaped nuclei with grooves and indentations, may or may not have well-demarcated cell borders - variable numbers of ordinary histiocytes and sometimes foam cells - common secondary components include eosinophils, may form aggregates surrounded by histiocytes and Langerhans' cells, neutrophils, lymphocytes and plasma cells