[60] Cellular Angiofibroma with Atypia and Sarcomatous Transformation

E Chen, CDM Fletcher. Brigham and Women's Hospital, Boston, MA

Background: Cellular angiofibroma occurs equally in men and women and commonly arises in the inguino-scrotal or vulvovaginal regions. A prior study of 51 cases from our group showed that the tumor follows a benign course without any tendency for recurrence. In 1 prior case, an intralesional microscopic nodule of pleomorphic liposarcoma was observed. The biologic significance of atypia or sarcomatous transformation in cellular angiofibroma remains uncertain. In this study, we characterized clinicopathologic features in 11 cases of cellular angiofibroma with atypia or sarcomatous transformation.
Design: Eleven cases identified between 2001 and 2009 were retrieved from consultation files. Clinical details and follow-up were obtained from the referring pathologists. H&E-stained sections of all cases were re-examined. Immunohistochemical studies were performed on available unstained sections.
Results: Lesions arose in 11 women ranging in age from 39 to 71 years (median, 46 years). Tumor size ranged from 1.2 to 7.5 cm. In 10 cases, the tumors occurred in the vulva, and one occurred in the hip region. There were 3 cases of cellular angiofibroma with atypia. Two showed severely atypical cells and frequent mitotic figures scattered within the cellular angiofibroma. One case showed a discrete nodule of atypical cells. Eight cases of cellular angiofibroma showed sarcomatous transformation. In each case, abrupt transition to a discrete area of more pleomorphic, hypercellular tumor was seen. The sarcomatous component in 2 cases showed features of pleomorphic liposarcoma. Two cases showed a discrete nodule of atypical lipomatous tumor within cellular angiofibroma. In the remaining 4 cases, the sarcomatous component was composed of pleomorphic spindle cells. By immunohistochemistry, atypical cells and sarcomatous areas showed either multifocal or diffuse p16 expression compared to either scattered or negative expression in cellular angiofibroma. Follow-up information was available for 7 patients (range from 2 months to 75 months; median 21 months). To date, 6 patients did not develop recurrence or metastasis. One patient died of carcinoma of unknown primary.
Conclusions: Cellular angiofibroma with atypia or morphologic sarcomatous transformation occurs predominantly in the subcutaneous tissue of the vulva and, as yet, shows no evident tendency to recur based on clinical follow-up available for 7 cases. The sarcomatous component can show variable features including atypical lipomatous tumor, pleomorphic liposarcoma or pleomorphic sarcoma NOS. Overexpression of p16 suggests a possible underlying molecular mechanism.
Category: Bone & Soft Tissue

Monday, March 22, 2010 1:00 PM

Poster Session II # 17, Monday Afternoon

 

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