Circumscribed acral hypokeratosis.

BACKGROUND Circumscribed acral hypokeratosis (CAH) is an idiopathic condition that typically presents as an acquired, solitary, asymptomatic, well-defined, depressed, flat-based deformity, with a slightly raised border on the palm or, rarely, the sole. Histologically, the lesional epidermis is depressed with a characteristic, abrupt, hyperkeratotic, slightly-raised ridge at the transition from normal skin. OBJECTIVE We sought to present 3 additional cases of CAH. METHODS A review of 3 cases of CAH was performed. Liquid phase polymerase chain reaction (PCR) was conducted to evaluate for human papillomavirus (HPV). RESULTS Three cases of CAH were reviewed. One patient had a history of a burn at the site prior to developing the disorder while another patient, as a child, had a history of verruca plantaris in the same location. Lesions were solitary, involving the palm or sole, in 2 cases and in one case they were multiple involving both the palms and the soles. HPV testing detected HPV type 6 in the lesion of one patient who previously was treated for warts in the same location. Topical fluorouracil, calcipotriol ointment under occlusion, and clobetasol ointment under occlusion were unsuccessful in one patient. LIMITATIONS In case 2, we were pathology consultants and unable to evaluate the clinical appearance of the lesion. CONCLUSIONS CAH may involve palms and/or soles. Lesions may be solitary or multiple, and vary widely in size. We believe that CAH most likely represents a reaction pattern developing in response to various stimuli, including trauma, HPV, or both.