Rare Case of Trichogenic Tumor: Trichoblastic Carcinoma

Adnexal tumors of the hair follicle demonstrate differentiation toward hair follicle structures. Trichoblastic carcinoma is a rare malignant adnexal tumor that is characterized by two distinct forms, low- and high-grade forms, which have been reported in the literature. A 59-year-old man visited our clinic with a 25-year history of an asymptomatic papule in the region of the right temporal fossa. The diagnosis of a low-grade trichoblastic carcinoma was made on the basis of histopathological examination. The history and overall behavior of this tumor remains unknown because of the low incidence rate; therefore, it is important to differentiate it from basal cell carcinoma. We report this case because of its rarity in the literature.