Proliferating trichilemmal cyst with malignant transformation

A proliferating trichilemmal cyst is a rare but morphologically distinctive tumour usually occurring in the scalp of elderly women. The even rarer malignant proliferating trichilemmal cyst has been reported in about 30 patients until now. A case of such a malignant tumour occurring on the ear of a 79 year-old male is presented. The clinical presentation, histological appearance, treatment and differential diagnosis is presented and discussed.