A pigmented macule on the palm

A 4 year old boy was brought to the paediatric dermatology department by his parents because they had noticed a small light brown spot on his left palm, which had been growing progressively over the past year. The child had been seen previously by a dermatologist, who suspected melanoma and referred him. The lesion had shown no signs of prior inflammation or trauma. Apart from palm hyperhidrosis (excessive sweating), the child was in good health. He had no family history of similar conditions, and had not travelled abroad.

On examination, a well defined brown macule was visible on the index finger side of the left palm, measuring 2.0 × 1.2 cm (fig 1). No other skin or mucous membrane lesions were detected. Dermoscopy revealed a reticular pigmentation consisting of thin bundles of brown spicules arranged in parallel lines in certain peripheral areas (fig 2). Given the acral location of …