Phyllodes tumor (PT) of the vulva is very rarely seen and has been reported in only 17 cases in English literature. It is still uncertain that proliferative mammary gland lesions including PT in the anogenital region originate from ectopic breast tissue or from local adnexal structures. We report a case of primary benign PT of the vulva in a 41-year-old female patient. Microscopic examination revealed biphasic tumoral formation with typically extensive leaf-like papillary structures growing toward slit-like spaces under the skin. In immunohistochemical examination, more than 50% of epithelial cells showed a positive reaction with ER, PR, and panCK and a focal positive reaction with GCDFP-15. Myoepithelial cells showed a positive reaction with SMA, CD10, and WT-1. In this report, we underline the clinicopathologic features of PT localized to an unusual site, and also discuss its etiology, differential diagnosis in the light of the current literature.
Keywords: Vulva, phyllodes tumor, skin, benign