Café-au-lait macules overlying segmental macular hyperpigmentation in a pediatric patient: an early sign for mosaic neurofibromatosis type 1.

The presentation of multiple café-au-lait macules (CALMs) in children is a common reason for referral to a dermatologist. Segmental CALMs, a subtype of CALMs, is usually limited to a specific part of the body. Mosaic neurofibromatosis type 1 (NF1; OMIM 162200) is a common congenital disorder associated with segmental CALMs with an incidence of about 1 case/40000 patients, which is lower than the prevalence of patients with germline NF1 mutations1,2 .