Tiny Tot, Big Lesion

About six months ago, the parents of this 1-year-old boy first noticed the lesion on his shoulder. It started as a pinpoint papule but has grown to its current size—at which point, it caught their full attention. Although there are no associated symptoms, the parents request referral to dermatology to clear up the matter.

The child is reportedly healthy in all other respects, maintaining weight as expected, and normally active and reactive to verbal and visual stimuli.

EXAMINATION

A distinctive orangish brown, ovoid, 8 x 4–mm nodule is located on the child’s right superior shoulder. The lesion has a smooth, soft surface, and there is no tenderness on palpation. No additional lesions are seen elsewhere.

Eye examination reveals normal and symmetrical red reflexes.

What is the diagnosis?