| A | B |
|---|
| Fascicles of eosinophilic spindle cells intersecting at right angles | Smooth muscle |
| Short fascicles of spindle cells radiating from a central point (like spokes on a wheel)-storiform | Fibrohistiocytic |
| Nuclei arranged in columns-palisading | Schwann cell |
| Herringbone | Fibrosarcoma |
| Mixture of fascicles of spindle cells and groups of epithelioid cells-biphasic | Synovial sarcoma |
| Extraosseous Ewing sarcoma and primitive neuroectodermal tumor | FLI-1-EWS fusion gene |
| Liposarcoma-myxoid and round cell type | CHOP/TLS fusion gene |
| Synovial sarcoma | SYT-SSX fusion gene |
| Rhabdomyosarcoma- alveolar type | PAX3-FKHR fusion gene |
| Extraskeletal myxoid chondrosarcoma | CHN-EWS fusion gene |
| Desmoplastic small round cell tumor | EWS-WT1 fusion gene |
| Clear cell sarcoma | EWS-ATF1 fusion gene |
| Dermatofibrosarcoma protuberans | COLA1-PDGFB fusion gene |
| Alveolar soft part sarcoma | TFE3-ASPL fusion gene |
| Congenital fibrosarcoma | ETV6-NTRK3 fusion gene |
| Tumors expressing spindle cell | Fibrous, fibrohistiocytic, smooth muscle, Schwann cell |
| Tumors expressing small round cell | Rhabdomyosarcoma, primitive neuroectodermal tumor |
| Tumors expressing epithelioid | Smooth muscle, Schwann cell endothelial, epithelioid sarcoma |
| Well differentiated liposarcomas often possess | multinucleated floret or “flower-like”cells |
| characterized cytogenetically by the presence of a ring chromosome | liposarcoma |
| Myxoid liposarcoma , “round cell” liposarcoma | characteristic translocation: t(12;16). |
| Myxoid is a pathologic adjective for tissues that | have abundant hyaluronic acid-rich extracellular matrix;"ground substance" or connective tissue mucin |
| Pleomorphic liposarcoma | more likely to invade local tissues extensively and to metastasize widely |
| polyclonal in lineage | fibromatoses and fibroblastic proliferations |
| Palmar, plantar, penile fibromatose | Superficial, infiltrative and somewhat aggressive: |
| Nodular fasciitis, Myositis ossificans | Not usually aggressive, more of a mass, readily cured by simple excision |
| Deep-seated, mass forming and infiltrative, aggressive, hard to resect, often recur | Desmoid- abdominal, intrabdominal, extrabdominal |
| subcutaneous and superficial soft tissue of the volar area of the forearm in adults, frequently follows trauma | nodular fasciits |
| Microscopically, nodular fasciitis looks a lot like a sarcoma | non-neoplastic infiltrative proliferation of fibroblastic tissue that grows rapidly and is both cellular and mitotically active |
| Myositis ossificans | non-neoplastic, heterotopic bone formation in skeletal muscles |
| Myositis ossificans clinical | athletic adolescents and young a. present with a painful soft tissue swelling that shrinks into a discrete, hard mass |
| Myositis ossificans disease process | reactive bone formation: area of ossification within the muscle |
| Myositis ossificans treatment | local excision |
| in myositis ossificans the most atypical cells are found in | center of the lesion |
| in osteosarcoma, the most bizarre cells are to be found | (anywhere but especially) around the periphery of the neoplasm |
| fibromatosis | uncontrolled proliferations of fibroblastic tissue, can occur in palmar fascia leading to Duputreyn's contracture |
| Desmoid | aggressive fibromatosis that tends to arise in the skeletal musculature and abdominal region of adults |
| Abdominal Desmoid | particularly common in abdominal wall of pregnant women |
| intrabdominal Desmoids | often in the mesentery and associated with Gardner syndrome |
| High power field of an H&E stained section of a desmoid tumo | shows uniform fibroblastic cells with bland nuclei. |
| Neurofibromas | benign, spindle cell tumors that arise in association with peripheral nerves |
| Neurofibroma immunohistochemistry | express some antigens common to Schwann cells |
| multiple neurofibromas occur in | von Recklinghausen's neurofibromatosis |
| Fibrosarcoma | Microscopically characterized by a herringbone weave pattern |
| Fibrosarcoma | malignant tumor arising in deep soft tissue, usually in adults |
| Dermatofibroma | characteristic histologic pattern called "storiform." spindle cells arranged in pinwheel pattern |
| Malignant Fibrous Histiocyoma (MFH) | most common of the soft tissue sarcomas and most common post-radiation sarcoma |
| It may arise de novo or in a previously radiated site with the peak incidence being the seventh decade. | Malignant Fibrous Histiocyoma (MFH) |
| storiform pattern intermixed bizarre, cytologically malignant giant cells | Microscopically, the MFH is composed of |
| immunocytochemistry: express enzymes characteristic of, but not unique to, macrophages | malignant giant cells of MFH |
| Embryonal Rhabdomyosarcoma | malignant tumor in young pedes, arises in preexisting spaces or potential spaces |
| Embryonal Rhabdomyosarcoma "sarcoma botryoides" sites | the middle ear, the vagina, the bladder, the nose, the orbit |
| "sarcoma botryoides." | a polypoid mass that can take on the shape of a bunch of grapes |
| Embryonal Rhabdomyosarcoma by electron microscopy | sarcomeres can be seen |
| Embryonal Rhabdomyosarcom immunocytochemistry | antigens characteristic of muscle actin, desmin, myoglobin |
| Embryonal Rhabdomyosarcoma Histologically | "strap" cell that has more abundant, eosinophilic cytoplasm and cross striations; |
| Alveolar Rhabdomyosarcoma | subtype of rhabdomyosarcoma more likely to involve the extremities and occurs in older children and young adults |
| Alveolar Rhabdomyosarcoma Histologically | vaguely resembles lung; interwoven fibrous septa of background connective tissue create spaces lined by malignant cells |
| chimeric fusion protein PAX3-FKHR | may lead to dysregulation of muscle differentiation |
| PAX3 gene | encodes a transcription factor involved in skeletal muscle development |
| FKHR gene | encodes widely expressed transcription factor |
| Alveolar Rhabdomyosarcoma recurring chromosomal translocations | t(2;13)(q35;q14) |
| causes transformation by inappropriately activating PAX3 transcriptional targets | Alveolar Rhabdomyosarcoma chimeric fusion protein |
| Pleomorphic Rhabdomyosarcoma | occurs in deep soft tissues of adults, very aggressive, grows rapidly, dreadful prognosis |
| Pleomorphic Rhabdomyosarcoma microscopic appearance | composed of bizarre giant cells and malignant spindle cells that can exhibit cross striations |
| Pleomorphic Rhabdomyosarcoma immunohistochemistry | antigens typical of muscle cells (myoglobin) |
| Leiomyoma gross appearance | firm, white-tan whorled nodules |
| Leiomyoma | benign smooth muscle neoplasm extremely common in the female genital tract, often called "fibroids" |
| Leiomyosarcomas gross appearance | have a fish-flesh consistency and often show areas of hemorrhage and necrosis |
| Leiomyosarcomas microscopically | composed of malignant smooth muscle cells that exhibit cytologic atypia and mitotic activity. |
| Cytogenetically, synovial sarcoma is characterized by | a translocation involving the X chromosome t(x; 18). |
| Synovial sarcoma | arises from pluripotent mesenchymal stem cell (NOT synovium) |
| SYT gene on chromosome 18 fuses with the SSX gene on the X chromosome | synovial sarcoma chimeric protein |
| Synovial Sarcoma incidence | occurs in the legs in approximately 2/3 of cases; persons between the ages of 16 and 25 y. |
| Microscopically, synovial sarcoma is... | characterized by a biphasic histologic appearance with malignant spindle and epitheliod cells |
| Synovial sarcoma is an unusual sarcoma because… | It metastasizes to regional lymph nodes rather than hematogenously |
| synovial sarcoma has | epithelioid regions that express keratin and gland-like spaces lined by cuboidal cells |
| Giant Cell Tumor of Tendon Sheath (GCTTS) , and Pigmented Villonodular Synovitis | actually do arise from the synovial membrane |
| golden yellow color secondary to hemosiderin deposition | Giant cell tumor of tendon sheath gross appearance |
| Giant cell tumor of tendon sheath clinical | usually presents as an isolated, slowly enlarging, painless mass on the finger |
| Pigmented villonodular synovitis | usually involves the knee joint and produces pain, swelling, and locking of the joint. often recurs after surgery |
| PVNS | a diffuse, red-brown villous proliferation that can even erode adjacent bones |
| Mixture of fascicles of spindle cells and groups of epithelioid cells-biphasic | Synovial sarcoma |
| Tumors expressing spindle cell | Fibrous, fibrohistiocytic, smooth muscle, Schwann cell |
| Tumors expressing small round cell | Rhabdomyosarcoma, primitive neuroectodermal tumor |
| Tumors expressing epithelioid | Smooth muscle, Schwann cell endothelial, epithelioid sarcoma |
