Angiomyofibroblastoma
Definition
- Circumscribed edematous lesion of the external genitalia and perineal soft tissue
Diagnostic Criteria
- Restricted to external genitalia and perineal soft tissue
- Rare in males
- Most under 5 cm
- Circumscribed with thin pseudocapsule
- Edematous background with prominent vascularity
- Thin walled dilated capillaries and venules
- Scattered bundles of collagen
- Occasionally sclerotic
- No necrosis
- Alternating hypercellular and hypocellular areas
- Cells frequently aggregated around vessels
- Nests and occasional solid compact foci
- Also scattered individual cells
- Hypocellular areas can resemble aggressive angiomyxoma except the vessels are not as thick walled
- Spindle to round cells
- May be epithelioid
- May have plasmacytoid appearance
- Eosinophilic cytoplasm, occasionally hyaline
- Bland to minimally atypical oval nuclei
- Inconspicuous nucleoli
- Mitotic figures rare, no atypical mitotic figures
- Binucleate and multinucleate cells common
- Cells frequently aggregated around vessels
- Frequently fat in lesion
- Not clear if this is entrapped or lesional fat
- May occasionally be prominent ("lipomatous variant")
- Two reported scrotal lesions were predominantly adipose tissue
- Occasional findings
- Prominent spindle cell population
- Stellate cells
- Degenerative nuclear hyperchromasia
- Mast cells may be numerous
Richard L Kempson MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting:: May 27, 2007