Seborrhoeic keratosis or occult malignant neoplasm of the skin?

Background: Seborrhoeic keratosis is generally considered to be a benign lesion of the skin.

Observation: We present the case of a 68-year-old male who presented with clinically typical seborrhoeic keratosis that later histological examination showed partially covered an occult basal cell carcinoma.

Objective: To have an indication of what percentage of clinically apparent seborrhoeic keratoses may be associated with some form of histologically proven skin malignancy.

Methods: We carried out a retrospective analysis of approximately 23,000 histopathological examinations done on specimens from dermatological lesions.

Results: Fifty-nine (11.9%) clinically apparent seborrhoeic keratoses were later histologically diagnosed as basal cell carcinomas, 17 (3.4%) as squamous cell carcinomas, and five (1.01%) as malignant melanomas.

Conclusions: Although the association of seborrhoeic keratosis and skin malignancy appears to be relatively uncommon, the possibility of such an association cannot be ruled out.