Segmental neurofibromatosis presenting with congenital excessive skin folds

Segmental neurofibromatosis (SNF) is a rare type of neurofibromatosis (NF-1) resulting from post-zygotic somatic mutations in the neurofibromin gene that leads to mosaicism. Reported manifestations of SNF include neurofibromas, freckling, or café-au-lait spots limited to a single body region or limb. We present a 5-month-old male referred to our clinic for evaluation of congenital excessive skin folds on the back. A mildly erythematous, poorly demarcated soft plaque was noted, consisting of excessive skin folds. A cluster of light brown hyperpigmented macules was seen overlying the plaque. A punch biopsy of the plaque confirmed a diagnosis of neurofibroma. Further investigation ruled out other manifestations of NF-1. The early onset of our patient’s neurofibroma and its gross appearance with redundant skin folds are all unusual features. To our knowledge, congenital excessive skin folds found in a single tumor have not been previously described in the literature as a manifestation of SNF. Clinicians should be educated about the possibility of congenital localized skin folds in association with SNF in order to identify the disease in infancy and monitor any changes in neurofibroma pathology.