Adult Fibrosarcoma
Definition
- Malignant neoplasm composed of uniform, cytologically malignant spindled fibroblasts or myofibroblasts occurring over age 10
Diagnostic Criteria
- A diagnosis of exclusion after other spindle cell sarcomas have been excluded
- As currently defined, it is a rare tumor
- Over age 10 years
- Uniform cytologically atypical spindle cells
- Elongate nuclei
- Hyperchromatic, granular chromatin
- Nucleoli may be multiple and prominent
- Mitotic figures usually frequent and abnormal
- Scant cytoplasm
- Broad cellular fascicles
- Frequent herringbone pattern (intersection at acute angles)
- May be long sweeping fascicles
- Stroma scant to collagenous
- Diffuse collagen abundant only in low grade tumors
- Rarely keloid like collagen bundles
- Stroma may be focally myxoid
- Infrequent cartilaginous or osseous metaplasia
- Areas indistinguishable from fibromatosis may be present
- Immunohistochemistry must not show evidence of specific differentiation
- Keratin, desmin, CD34, S100 negative
- Actin variable
- See separate entities:
Richard L Kempson MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting: October 15, 2007
Last Update: January 26, 2008
