8103/0 Pilar tumor


Proliferating trichilemmal cyst
Proliferating trichilemmal tumor


ICD-O-3 topography code: C44

A neoplasm with tricholemmal differentiation. It usually presents on the scalp as a solitary, multilobular, large, exophytic mass and affects women more frequently than men. Histologically, it may display benign cytological features and appear as a circumscribed solid-cystic neoplasm or it may display malignant characteristics and invasive features. Cases without malignant characteristics usually have an indolent course. Complete surgical excision is recommended in such cases to avoid recurrences and to allow complete examination of the specimen. Cases with malignant features may be locally aggressive and recur or metastasize.