1. Specimen evaluation 1 Specimen Type...... 1 Clinical History...... 1 Radiologic Correlation ...... 1 Special Studies ...... 1 Immunohistochemistry ...... 2 Electron Microscopy...... 2 Genetics...... 3 Recognizing Non-Soft Tissue Tumors...... 3 Grading and Prognostication of Sarcomas...... 3 Management of Specimen and Reporting...... 4 2. Nonmalignant Fibroblastic and Myofibroblastic Tumors and Tumor-Like Lesions . . . . 7 Nodular Fasciitis ...... 7 Proliferative Fasciitis and Myositis ...... 12 Ischemic Fasciitis ...... 18 Fibroma of Tendon Sheath...... 21 Nuchal-Type Fibroma ...... 24 Gardner-Associated Fibroma...... 27 Desmoplastic Fibroblastoma...... 27 Elastofibroma...... 34 Pleomorphic Fibroma of Skin...... 39 Intranodal (Palisaded) Myofibroblastoma...... 39 Other Fibroma Variants and Fibrous Proliferations ...... 44 Calcifying Fibrous (Pseudo)Tumor ...... 47 Juvenile Hyaline Fibromatosis...... 52 Fibromatosis Colli...... 54 Infantile Digital Fibroma/Fibromatosis...... 58 Calcifying Aponeurotic Fibroma...... 63 Fibrous Hamartoma of Infancy ...... 65 Myofibroma/Myofibromatosis ...... 69 Palmar/Plantar Fibromatosis...... 80 Lipofibromatosis...... 85 Diffuse Infantile Fibromatosis...... 90 Desmoid-Type Fibromatosis ...... 92 Benign Fibrous Histiocytoma (Dermatofibroma)...... 98

xi Tumors of the Soft Tissues

Non-neural Granular Cell Tumor...... 104 Neurothekeoma ...... 104 Plexiform Fibrohistiocytic Tumor...... 110 Superficial Acral Fibromyxoma ...... 113 Superficial Angiomyxoma (Cutaneous Myxoma)...... 118 Intramuscular Myxoma...... 125 Juxta-articular Myxoma...... 128 Aggressive Angiomyxoma ...... 128 Angiomyofibroblastoma...... 135 Cellular Angiofibroma...... 136 3. Fibroblastic/Myofibroblastic Neoplasms with Variable Biologic Potential...... 165 Solitary Fibrous Tumor ...... 165 Dermatofibrosarcoma Protuberans...... 169 Giant Cell Fibroblastoma ...... 177 Low-Grade Fibromyxoid Sarcoma...... 181 Sclerosing Epithelioid Fibrosarcoma ...... 185 Inflammatory Myofibroblastic Tumor...... 186 Inflammatory Myxohyaline Tumor of Distal Extremities (Acral Myxoinflammatory Fibroblastic Sarcoma)...... 190 Infantile Fibrosarcoma (Congenital Fibrosarcoma) ...... 192 Adult Fibrosarcoma and Myofibroblastic Sarcoma ...... 193 Myxofibrosarcoma...... 196 Malignant Fibrous Histiocytoma/Undifferentiated Pleomorphic Sarcoma ...... 203 Pleomorphic Hyalinizing Angiectatic Tumor...... 209 Giant Cell Tumor of Soft Parts and Giant Cell Malignant Fibrous Histiocytoma . . . . 210 4. Lipomatous Tumors...... 223 Lipoma and Variants ...... 223 Ordinary Lipoma...... 224 Lipoma with Metaplastic Cartilage and Bone...... 226 Lipomatosis of the Nerve ...... 226 Angiolipoma...... 227 Spindle Cell Lipoma and Pleomorphic Lipoma...... 229 Chondroid Lipoma...... 233 Hemosiderotic Fibrohistiocytic Lipomatous Lesion/Tumor ...... 235 Hibernoma...... 236 Lipoblastoma ...... 238 Massive Localized Lymphedema in the Obese ...... 240 Liposarcoma...... 240 Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma...... 240

xii Contents

Dedifferentiated Liposarcoma ...... 248 Spindle Cell Liposarcoma...... 254 Myxoid Liposarcoma...... 254 Pleomorphic Liposarcoma...... 259 5. Smooth Muscle Tumors...... 271 Angioleiomyoma ...... 271 Myopericytoma ...... 271 Glomus Tumor...... 274 Estrogen Receptor-Positive Smooth Muscle Tumors in Women...... 275 Epstein-Barr Virus–Associated Smooth Muscle Tumors ...... 279 Leiomyosarcoma...... 282 6. Tumors with Skeletal Muscle Differentiation...... 289 Rhabdomyomatous Mesenchymal Hamartoma ...... 289 Rhabdomyoma ...... 290 Rhabdomyosarcoma ...... 291 Embryonal Rhabdomyosarcoma ...... 292 Alveolar Rhabdomyosarcoma...... 298 Pleomorphic Rhabdomyosarcoma ...... 301 Sclerosing Rhabdomyosarcoma...... 303 7. Vascular Tumors...... 309 Papillary Endothelial Hyperplasia...... 309 Hemangiomas...... 309 Capillary Hemangioma ...... 311 Cavernous Hemangioma...... 311 Venous Hemangioma...... 311 Microvenular Hemangioma ...... 312 Intramuscular Hemangioma ...... 312 Cutaneous Arteriovenous Hemangioma...... 312 Epithelioid Hemangioma ...... 315 Glomeruloid Hemangioma ...... 320 Hobnail Hemangioma...... 323 Juvenile Capillary Hemangioma ...... 324 Lobular Capillary Hemangioma...... 324 Spindle Cell Hemangioma...... 326 Tufted Hemangioma...... 328 Verrucous Hemangioma...... 330 Lymphangioma (Lymphatic Malformation)...... 331 Lymphangiomatosis ...... 334 Lymphangioendothelioma (Acquired Progressive Lymphangioma) ...... 335

xiii Tumors of the Soft Tissues

Retiform Hemangioendothelioma ...... 336 Papillary Intralymphatic Angioendothelioma...... 337 Kaposiform Hemangioendothelioma...... 337 Epithelioid Hemangioendothelioma...... 338 Epithelioid Sarcoma-Like Hemangioendothelioma ...... 340 Angiosarcoma ...... 345 Kaposi Sarcoma...... 350 8. Soft Tissue Tumors with Cartilaginous or Osseous Differentiation...... 363 Soft Tissue Chondroma...... 363 Extraskeletal Myxoid Chondrosarcoma ...... 364 Extraskeletal Mesenchymal Chondrosarcoma ...... 367 Myositis Ossificans and Related Osteocartilaginous Pseudotumors ...... 368 Extraskeletal Osteosarcoma ...... 372 Ossifying Fibromyxoid Tumor ...... 374 9. Soft Tissue Tumors with Epithelial Differentiation...... 381 Synovial Sarcoma...... 381 Epithelioid Sarcoma...... 387 Extrarenal Rhabdoid Tumor ...... 392 Mixed Tumor/Myoepithelioma...... 392 10. Miscellaneous Translocation Sarcomas ...... 401 Ewing Sarcoma/Peripheral Neuroectodermal Tumor...... 401 Desmoplastic Small Round Cell Tumor ...... 410 Clear Cell Sarcoma...... 416 Angiomatoid Fibrous Histiocytoma ...... 421 Alveolar Soft Part Sarcoma ...... 426 11. Miscellaneous Tumors ...... 435 Perivascular Epithelioid Cell Tumor...... 435 Phosphaturic Mesenchymal Tumor ...... 440 Tenosynovial Giant Cell Tumor ...... 447 12. Cytopathology of Soft Tissue Tumors and Tumor-Like Lesions...... 455 Fibroblastic, Myofibroblastic, and Fibrohistiocytic Tumors...... 456 Desmoid-Type Fibromatosis...... 456 Infantile Digital Fibroma/Fibromatosis...... 456 Nodular Fasciitis...... 456 Elastofibroma...... 459 Solitary Fibrous Tumor ...... 461 Dermatofibrosarcoma Protuberans ...... 462 Tenosynovial Giant Cell Tumor...... 462 Giant Cell Tumor of Soft Parts ...... 465

xiv Contents

Low-Grade Fibromyxoid Sarcoma...... 466 Undifferentiated Pleomorphic Sarcoma...... 467 Myxofibrosarcoma (Myxoid Malignant Fibrous Histiocytoma) ...... 470 Lipomatous Tumors...... 470 Lipoma/Hibernoma...... 470 Pleomorphic Lipoma...... 470 Spindle Cell Lipoma ...... 473 Myxoid/Round Cell Liposarcoma ...... 473 Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma...... 477 Dedifferentiated Liposarcoma ...... 477 Pleomorphic Liposarcoma...... 477 Myogenic Tumors...... 480 Leiomyoma...... 480 Leiomyosarcoma...... 480 Adult-Type Rhabdomyoma ...... 482 Rhabdomyosarcoma...... 483 Peripheral Nervous System Tumors...... 485 Benign Nerve Sheath Tumors (Neurofibroma and Schwannoma) ...... 485 Granular Cell Tumor ...... 485 Perineurioma ...... 485 Malignant Peripheral Nerve Sheath Tumor ...... 489 Vascular Tumors ...... 489 Lymphangioma ...... 489 Hemangioma ...... 489 Angiosarcoma ...... 489 Myxoid and Chondro-osseous Tumors and Tumor-Like Lesions...... 493 Intramuscular Myxoma/Soft Tissue Ganglion/Juxta-articular Myxoma ...... 493 Myositis Ossificans ...... 493 Extraskeletal Myxoid Chondrosarcoma ...... 495 Chordoma ...... 497 Extraskeletal Mesenchymal Chondrosarcoma...... 500 Unclassified and Miscellaneous Soft Tissue Tumors ...... 500 Synovial Sarcoma ...... 500 Extraosseous Ewing Sarcoma/Primitive Neuroectodermal Tumor Family...... 502 Epithelioid Sarcoma ...... 502 Alveolar Soft Part Sarcoma...... 502 Clear Cell Sarcoma ...... 506 Metastatic Malignant Melanoma ...... 506 Index ...... 513