A Case of Proliferating Trichilemmal Cyst with Trichoepitheliomatous Change

Proliferating trichilemmal cyst (PTC) was a rare benign neoplasm derived from the outer root sheath of anagen hair follicles, typically presenting as a solitary elevated mass on the scalp of elderly women. Histologically, it showed multiple lobules of squamous epithelium with abrupt keratinization and possible calcification. PTC could be associated with conditions like sebaceous nevus of Jadassohn and ectopic apocrine sweat glands. This document reported an unusual case of PTC with trichoepitheliomatous change in a young woman, highlighting a deviation from the typical demographic and presentation.