Circumscribed plantar hypokeratosis responding to topical calcipotriol

Abstract

Background: Circumscribed palmar or plantar hypokeratosis defines a benign condition clinically presented as a well-defined depressed area on the skin. It is characterized by a peculiar histopathological picture with the abrupt thinning of the horny layer of the epidermis.

Main observations: We present a case of a 17-year-old man, who presented with a one-year history of an occasionally painful lesion on his right sole. The diagnosis of circumscribed plantar hypokeratosis was confirmed by histopathology. The lesion was successfully treated with calcipotriol ointment.

Conclusions: Circumscribed palmar or plantar hypokeratosis is a benign condition that typically affects the hands. Different therapeutic approaches have been unsuccessful. In our patient the lesion was at a less frequent plantar location and the lesion responded to topical calcipotriol.

Keywords: atrophy; hyperkeratosis; hypokeratosis; keratin; palmar; plantar.

Figure 1

(A) Well-defined, depressed and erythematous lesion on the sole. (The small black ring in the upper part of the lesion was caused by coagulation with silver nitrate due to bleeding of the curetted area.) (B) Resolution after treatment with calcipotriol ointment.

Figure 2

(A) Sharp transition between normal and involved skin, which shows marked decrease of horny cell layer thickness. (Hematoxylin and eosin x40.) (B) Preserved granular cell layer thickness and absence of parakeratosis in the depressed area. (Hematoxylin and eosin x100.)