Seborrheic keratosis with trichilemmomas masquerading as melanoma.

Seborrheic keratoses are benign lesions and, generally, are easily diagnosed based on clinical criteria. However, several types of benign as well as malignant lesions have been found associated with seborrheic keratoses, thus confusing the clinical picture. Presented is the first reported case of trichilemmomas occurring within seborrheic keratosis and masquerading as melanoma with regression. Biopsy of unusual seborrheic keratoses is recommended.