Proliferating trichilemmal tumor (PTT), still referred to as proliferative trichilemmal cyst (TC), is an uncommon malignant adnexal tumor originating from the cells of the outer root sheath of the hair follicle or, more often, from a trichilemmal cyst, following multiple trauma and/or recurrent inflammation. We report the case of a 64-year old female patient, with no particular previous history, presenting with tumor of the scalp gradually evolving over 18 months. Clinical examination showed a painless, firm, adhering ulcero-budding tumor mass measuring 12 cm along its longer axis at the level of the vertex. The patient had clinically negative lymph nodes. Histological examination showed malpighian cell proliferation arranged in clumps and coalescing lobules with focal areas of abrupt trichilemmal keratinization, with very marked atypies cyto-nuclear and an infiltrated fibrous stroma, suggesting proliferating trichilemmal tumor. Staging evaluation showed no metastase. The patient underwent wide surgical resection followed by in depth removal of extra tissue, without recurrence at 3-months' follow-up.
Keywords: Proliferating trichilemmal tumor; malignant; scalp.