Angiomyofibroblastoma of the vulva: A mitotically active variant?

A case of angbmyofibrobiastoma in a 48-yearold woman is reported. The tumor occurred as a left vulval mass and was treated by simple excision. It was located in the subcutaneous tissue of the left vuiva and was well circumscribed, measuring 2.8 × 2.7 × 2.5 cm. Microscop Ically, the tumor was composed of hypocellular and cellular arees with well-developed small vessels. Spindle or polygonal cells were arranged with perlvascular accentuation In an edematous or fibrocollagenous background. Some spindle-shaped or polygonal stromal cells were also arranged in epithelioid nests. In some areas, mitosas were frequent (maximum 3/10 high-power field). lmmunohistochemicaily, the stromal cells were positive for vimentln and desmin, but negative for α-smooth muscle actin, S-100, neurofilament, estrogen receptor, progesterone remptor, CD31 and CD34. The average labeling index of Kl-67 In stromal cells was 3.1%. Ultrastructural analysis demonstrated that the stromal cells adhered with primitive Junctions and contained lntermediate filaments with no focal density In the cytoplasm. These findings were consistent with anglomyofibrobiastoma, although previously reported cases did not show so many mitoses. Therefore, this case was suggested to be a mitotically active variant.