Two cases of pedunculated inverted follicular keratosis

Inverted follicular keratosis is a benign, solitary skin lesion that is mainly diagnosed histologically, rather than clinically. The pathogenesis of inverted follicular keratosis has not been elucidated. It is still controversial as to whether the inverted follicular keratosis is a distinct hair follicle lesion, an old lesion of verruca vulgaris, or an irritated seborrheic keratosis. It is usually presented with a verrucous firm papule or nodular lesion clinically, and it commonly mimics other proliferative skin lesions, such as warts, cutaneous horn and basal cell carcinoma. However, inverted follicular keratosis with a pedunculated feature has been hardly found. Clinical morphology of the inverted follicular keratosismight be related with the site of tumor origin. Herein, we report two interesting cases of inverted follicular keratosis with a peculiar pedunculated feature.