Case presentation

A large pigmented lesion was noted across the back on a baby boy at birth. He was born to non-consanguineous parents and by an uncomplicated vaginal delivery at 38+1 weeks. He weighed 2.62 kg. There is no family history of similar skin conditions.

On examination, there was a large, asymmetrical, heterogeneously pigmented lesion covering most of his back, extending to the buttocks (figure 1). The margins were irregular and did not contain any hair. It measured 21 cm. There were smaller lesions on his face, scalp and lower limbs (figure 2). No other congenital abnormalities were noted. Postnatal baby check including neurological examination was normal.

Test your knowledge

1. What is the most likely diagnosis?

   1. Large congenital melanocytic naevus.

   2. Plexiform neurofibroma.

   3. Becker’s melanosis.

   4. Smooth muscle hamartoma.

2. Which complication of this condition is the patient at most risk …