Huge pedunculated angiomyofibroblastoma of the vulva

We present the case of a huge pedunculated benign mesenchymal myxoid tumor that developed on the right labia majora of a 48-year-old-woman. The excised mass weighed 4534 g and was 23 cm in diameter; the cut surface was yellowish and elastic. Microscopic examination revealed spindle and plump oval tumor cells arranged with abundant capillary vessels in an edematous stroma. Immunohistochemical staining showed that the tumor cells were positive for vimentin, desmin, estrogen receptor, and progesterone receptor, but negative for alpha-smooth muscle actin, CD34, CD45, CD68, and S-100. Based on these features, the pathological diagnosis was angiomyofibroblastoma. A pedunculated angiomyofibroblastoma is extremely rare and, to the best of our knowledge, this is the biggest such tumor in terms of size and weight reported to date. It is especially important in such a huge mass greater than 10 cm that angiomyofibroblastoma is differentiated from aggressive angiomyxoma, which is a deeply invasive and recurrent neoplasm.