(BMJ)—An otherwise healthy 3-year-old girl presented with multiple hypopigmented lesions that she’d had since birth. Exam: ~20 pale macules and patches on trunk and neck, with limited vascularity after rubbing, and ~30 well-demarcated brown macules (0.2-1.0 cm). What’s the dx?
You are correct. She had a combination of café au lait macules (CALMs) and nevus anemicus lesions. In patients with multiple CALMs, multiple nevi anemicus can be an early sign of neurofibromatosis type 1 (NF1). Molecular testing of the NF1 gene showed a heterozygous nonsense variation of c.4537C>T (p.R1513*), pathognomonic of NF1. The presence of >6 CALMs suggests an underlying genetic condition, most commonly NF1. Less common inherited disorders associated with CALMs include Legius syndrome, Noonan syndrome, LEOPARD syndrome, piebaldism, and familial progressive hyperpigmentation.
Nevus anemicus is a congenital skin hypopigmentation caused by permanent vasoconstriction in the superficial dermis. It presents as pale macules and patches with limited vascularization after rubbing or warming and is associated with genetic syndromes, including NF1, tuberous sclerosis, and phacomatosis pigmentovascularis.
By age 5, the patient had developed bilateral freckling in the axillary and inguinal regions, further consolidating the NF1 dx, but she had no evidence of complications involving the eyes, nervous system, CV system, endocrine system, or bone. She required no tx but continues to be monitored.
BMJ 2021;372:m4844
