Nevus anemicus associated with neurofibromatosis type 1 in a neonate: a case report.

Neurofibromatosis type 1 (NF1) is a multisystemic autosomal dominant disease affecting approximately 1 individual in 3500. The diagnostic criteria developed by NIH in 1988 allow unequivocal diagnosis in all cases but the youngest children. Due to the variable phenotypic expression, the diagnosis of NF1 in the youngest may be challenging, particularly when the distinctive cutaneous lesions are missing. We describe the case of a neonate who presented at birth solely with a nevus anemicus. Although this is not considered a diagnostic feature, given the presence of a few café au lait lesions in the patient's father, the genetic test was performed and the diagnosis of NF1 confirmed. To our knowledge, the association between nevus anemicus and NF1 is only anedoctal. The peculiarity clinical manifestation of this case highlights the high variable expressivity of the NF1 gene mutation and reinforces the importance of genetic counseling in affected individuals.