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Soft Tissue Tumors
Lucy H. Liu, M.D.Department of Pathology
University of Illinois at Chicagoe-mail: [email protected]
Soft Tissue Tumors
UIC College of MedicineM2 Pathology Course, Lecture # 63
Tuesday, January 28, 200311:30 am
Soft Tissue Tumors
Lecture Goals:
1. Nomenclature & classification system of tumors
2. Differences between benign and malignant tumors
3. Clinical & morphologic features of common tumors
4. Approach to diagnosis of soft tissue tumors
Soft Tissue Tumor
Neoplastic conditions arising in extraskeletal mesodermal tissues
-- Skeletal muscle
-- Fibrous tissue-- Smooth muscle
-- Blood & lymphatic vessels-- Peripheral nerves - neuroectoderm
-- Adipose tissue
Soft Tissue TumorGeneral principles for diagnosis:
-- Deep lesions tend to be malignant
-- Larger tumors tend to be malignant
Location
Size
-- Superficial lesions - benign
-- Rapidly growing - malignant
Growth pattern
-- Infiltrating - malignant
Metastasis-- Malignant
Soft Tissue Tumors
Histological morphologyImmunohistochemistryCytogenetic studyMolecular analysisUltrastructure
Approach to Diagnosis
Soft Tissue Tumors
Cytokeratin Vimentin Smooth muscle actin Desmin S-100 CD 31 CD 34
Immunohistochemistry
Soft Tissue Tumors
t( 2:13) Alveolar rhabdomyosarcoma t( 11;22) Ewing’s sarcoma/PNET t( 11;22) Desmoplastic small round cell tumor t( 12;16) Myxoid liposarcoma t( 9;22) Myxoid chondrosarcoma t(12;22) Clear cell sarcoma t( X;18) Synovial sarcoma
Cytogenetic Changes
Nodular Fasciitis Benign reactive soft tissue lesion Probably secondary to trauma On forearm, trunk, back- well circumscribed Spindle cells ( fibroblasts & myofibroblasts) in loose matrix -“fibroblasts in tissue culture” Rapid growth, frequent mitotic figures Self-limited, cured by excision Must differentiate from a sarcoma
Fibromatosis
Fibroproliferative lesions
Desmoid - Infiltrative masses in abdominal, extra-abdominal & intra-abdominal
Fibroblasts & Myofibroblasts
Palmar, plantar fibromatosis Surgical excision
Infiltrative growth pattern Tendency to recur
Fibrosarcoma Malignant tumor of fibroblast origin In adults, in lower extremities, upper extremities, trunk
Increased cellularity, high nuclear-cytoplasmic ratios
Spindle cells in a herringbone pattern
Must exclude other tumors which resemble fibrosarcoma
- Peripheral nerve sheath tumor- Synovial sarcoma
Dermatofibroma
Benign fibrous histiocytoma
Usually in skin
Mixture of fibroblasts, myofibroblasts, histiocytesSurgical excision
Dermatofibrosarcoma Protuberans (DFSP)
Fibrohistiocytic tumor Intermediate malignant potential In skin & subcutis Spindle cells in storiform pattern Local recurrence CD 34 Transformation to fibrosarcoma Surgical excision
Malignant Fibrous Histiocytoma
Malignant soft tissue tumor with histocytic differentiationMost common type of soft-tissue sarcomaMost frequently encountered sarcoma post radiation therapyIn adults, in deep soft tissue - extremities & retroperitoneumMarked pleomorphism, spindle cells, storiform, myxoid
Leiomyoma
Benign soft tissue tumor
Arising in subcutaneous tissue or blood vessel wall Usually painful
Fascicles of regular smooth muscle cells
Leiomyosarcoma Malignant soft tissue tumor Arising in extremities of blood vessel wall Necrosis, hemorrhage Fascicles, nuclear atypia High mitotic activity
Rhabdomyosarcoma
Malignant tumor of striated muscle differentiation In children & young adults Several subtype
- Embryonal - Alveolar - Botryoid- Pleomorphic
Embryonal Rhabdomyosarcoma
Most common in children, in head & neck Most common subtype Rhabdomyoblasts with cytoplasmic cross-striation
Botryoid Rhabdomyosarcoma
Most common in hollow visceral organs - genitourinary tract
Polypoid, grape-like tumor masses
Scattered malignant cells in myxoid stroma
Alveolar Rhabdomyosarcoma
In extremities
Fibrous septa with loose clusters of rounded cells in center
- alveolar pattern
Pleomorphic Rhabdomyosarcoma
In skeletal muscles of older persons, in thigh
Marked pleomorphism
Irregularly arranged cells
Multinucleated giant cells
Lipoma Benign, well-circumscribed tumor of well-differentiated adipocytes
Usually subcutaneous, any site of adipose tissue Most common type of benign soft tissue tumor
In adult, upper back, neck, shoulder
Resemble normal adipose tissue Subtypes:angiolipoma, spindle cell lipoma
Liposarcoma Second most common sarcoma in adults
In deep compartments of extremities & retroperitoneum Lipoblasts Several subtypes- Well differentiated/atypical
lipoma- Myxoid / Round cell- Pleomorphic
Hemangioma
Benign lesion Resemble normal blood vessels Congenital or non-congenital Most common in infants & children Head & neck, internal organs - liver
Angiosarcoma
Malignant vascular tumor Many locations: skin, soft tissue, breast, live, spleen Irregular channels & atypical endothelial cells CD31- endothelial cell marker
Schwannoma
Benign tumor of neural differentiation - Schwann cells
Antoni A
Antoni B
In association with large nerve trunks Head & neck, extremities
-- Cellular area, palisaded nuclei
-- Less cellular area, myxoid background S-100
Synovial sarcoma Malignant soft tissue tumor
Arising in region of a joint & other sites of deep soft tissue
Unknown origin- misnomer
Multilobular Biphasic pattern
- spindle cells- epithelial - like cells
t( X;18 )