Infantile Fibrosarcoma
Definition
- Malignant neoplasm composed of uniform, cytologically malignant spindled fibroblasts or myofibroblasts occurring under age 10
Alternate/Historical Names
- Congenital fibrosarcoma
- Desmoplastic fibrosarcoma of infancy
- Juvenile fibrosarcoma
- Medullary fibromatosis of infancy
Diagnostic Criteria
- Under age 10 years
- Uniform spindle cells
- Elongate nuclei
- Scant cytoplasm
- May have round cell areas
- Must have conventional areas also
- Hyperchromatic, granular chromatin
- Nucleoli may be multiple and prominent
- Mitotic figures usually frequent and abnormal
- Broad cellular fascicles
- Frequent herringbone pattern (intersection of fascicles at acute angles)
- May be long sweeping fascicles
- Scant stroma
- Stroma may be focally myxoid
- Must have conventional areas also
- May have dilated congested vessels
- May have hemangiopericytic vessels
- Frequently scattered chronic inflammatory cells
- Immunohistochemistry must not show evidence of specific differentiation
- Actin variable
- Desmin, CD34, S100 negative
- 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
