[Giant seborrhoeic keratosis in an unusual site].

BACKGROUND: Seborrhoeic keratoses (SK) are benign tumours preferentially located on the head and trunk. We report a case of giant SK at an unusual site. PATIENTS AND METHODS: An 85-year-old man consulted for pigmented genital lesions present for 10 years. Clinical examination revealed small pigmented formations evoking SK and other pigmented, confluent and hyperkeratotic bordering plaques with a circinate contour. The latter lesions were biopsied, and histological findings were characteristic of SK and showed epidermal acanthosis associated with orthokeratotic invagination of the mucosa, resulting in the formation of characteristic wells. Treatment by electrocoagulation curettage was undertaken. DISCUSSION: SK are benign tumours that occur primarily in patients aged over 50 years. They are preferentially located in the trunk, head and neck. A genital site of SK is very unusual, with no more than 10 published cases. The cause of genital SK is as yet unknown, but data in the literature point to a possible role of chronic friction and HPV.