Trichoepithelioma: A Comprehensive Review.

Trichoepithelioma is an uncommon benign adnexal neoplasm. It can present as a solitary non-familial or multiple familial form. Trichoepithelioma usually develops in early childhood or puberty. Females are more affected. It is attributed to two genetic mutations on chromosomes 9p21 and 16q12-q13. Multiple familial trichoepithelioma is an autosomal-dominant disorder, characterized by numerous nodules and papules, predominantly on the face and occasionally on the scalp, neck, or upper trunk, positive family history, and histopathological findings. The lesions gradually increase in both size and number over time; however, they remain mostly asymptomatic. Although it is rare, trichoepithelioma lesions can undergo malignant transformation to trichoblastic carcinoma or basal cell carcinoma. Patients mainly seek treatment because the lesions are usually disfiguring and can lead to psycho-social issues. Non-pharmacologic approaches (e.g., excisional surgery, laser resurfacing), as the current mainstay of management, suffer from several drawbacks. New treatment techniques such as pharmacotherapy with potentially effective agents deserve more attention and investigation.