Syndromic nevoid hypermelanosis: description of seven cases with a 10-year follow up.

Skin lesions can often be the only sign of an underlying systemic abnormality which will require further investigation. Several syndromic conditions are diagnosed after their cutaneous marker, which is in most cases a nevus. We report a neurocutaneous condition which we named "syndromic nevoid hypermelanosis" (SNH). We studied seven patients who presented with hyperpigmented disseminated macules (melanotic or pigmented nevi) as a cardinal sign. Neurological abnormalities were detected in all cases and skeletal dysmorphism in four. In spite of the genetic alteration that may be the cause of this disease, dermatologists should be able to diagnose it based on its semiological features and distinguish it from other neurocutaneous conditions. We consider SNH to be a distinct clinical entity that has not been clearly defined until now.