[Malignant proliferating trichilemmal cyst of the scalp: A case report].

BACKGROUND: Proliferating trichilemmal cyst (PTC) is a rare adnexal tumor, generally benign, primarily sitting on the scalp of elderly women. About fifty cases are reported in the literature. Herein, we describe another one particularly aggressive. OBSERVATION: A 70-year-old woman had been showing an increase in the size of an occipital cyst for 6years. A cephalic scan and wide surgical excision had confirmed the diagnosis of a malignant PTC. Four months later, the tumor recurred with regional metastases and intracerebral invasion. DISCUSSION: Through our case and based on the literature analyzing, we discuss the nosology of PTC and its clinical and histological distinctive elements.
CONCLUSION: Large studies are needed to better understand the specificities of PTC, specially malignant form, but it remains difficult because of its rarity.