Proliferating trichilemmal tumor is a relatively uncommon tumor which develops preferentially as a solitary tumor on the scalp of elderly women. Histologically, the tumor i epresents a proliferation of the outer root sheath epithelium in a characteristic pattern, but the presense of cellular atypia, dyskera.totic cells and mitotic figures may lead to a false impression of squamous cell carcinoma. We report a case of proliferating trichliemmal tumor in a 70-yeiir-old male who presented with a slowly growing tumor on his right inguinal area for 2 years. This case is unusual in that the tumor occurred on the inguinal are anoher than the scalp in a male. (Kor J Dermatol 1993; 31(3): 434-438)