Hairy Hyperpigmented Lesion

December 20, 2013

A 16-year-old boy had an asymptomatic, hyperpigmented, hairy lesion on his left upper back. What's your diagnosis?

A 16-year-old boy had an asymptomatic, hyperpigmented, hairy lesion on his left upper back. The pigmentation, first noted 5 years earlier, had progressively spread across his torso. The medical history was uneventful.

What’s your diagnosis?