Trichoepithelioma and Basal Cell Carcinoma with Squamous Differentiation: Is it Causal or Coincidental?

Trichoepitheliomas (TEs) are benign cutaneous tumors that occur either as solitary non-familial or multiple familial. We report a case of multiple familial trichoepithelioma (MFT) in a 55-year-old female patient and her son who came with complaints of single ulcerated mass involving the left nasolabial fold and cheek. She had multiple papules and nodules all over the face and neck since 25 years. Histopathological examination of an ulcerated lesion revealed features of basal cell carcinoma (BCC) with squamous differentiation, which was confirmed by immunohistochemistry. A skin biopsy obtained from the papule on neck showed features of TE. However, whether BCC developed independently or by transformation from TE was uncertain. Her 36-year-old son presented with similar lesions on the face and a skin biopsy showed features of TE. Though malignant transformation of TE is quite rare, awareness of the potential for evolution of carcinoma in patients with MFT is important for management of these patients.