A cutaneous adnexal neoplasm with features of adamantinoid trichoblastoma (lymphadenoma) in the benign component and lymphoepithelial-like carcinoma in the malignant component: a possible case of malignant transformation of a rare trichoblastoma variant.

The authors describe a case of cutaneous adnexal tumor with a component reminiscent of adamantinoid trichoblastoma (lymphadenoma) that shows gradual transition to a high-grade carcinoma resembling lymphoepithelial-like carcinoma. The tumor was located above the upper lip of a 57-year-old woman and metastasized in regional lymph nodes. This seems to be the first documented report of malignant transformation of adamantinoid trichoblastoma. We discuss also other possibilities of histogenesis of this unique neoplasm.