Multiple inverted follicular keratoses as a presenting sign of Cowden's syndrome: case report with human papillomavirus studies.

Inverted follicular keratosis is characterized by a squamous epithelial expansion of the infundibular portion of the hair follicle in an exophytic and endophytic pattern. The lesion is often associated with squamous eddies similar to an irritated keratosis and may have a superficial papillomatous architecture. The lesion most often arises as a solitary nodule on the face of middle age to elderly individuals. Inverted follicular keratosis has been described as a distinct entity by some while others believe that it is related to trichilemmomas and/or verruca vulgares. The cutaneous pathology of Cowden's syndrome is characterized by multiple trichilemmomas. We present a woman who fulfills the clinical criteria for Cowden's syndrome and who initially presented with multiple inverted follicular keratoses. Also, in situ hybridization studies performed on the patient's keratoses do not reveal evidence of human papillomavirus infection.