Segmental Neurofibromatosis

This is an answer to the case – Numerous Soft, Nontender Papules and Nodules with Segmental Distribution

A 4-year-old girl presented for evaluation of cutaneous nodules that had been present on the left side of her trunk since birth. She had no history of seizures or developmental delay, and there was no family history of similar cutaneous findings.

Physical examination revealed numerous soft, nontender papules and nodules between 2 and 12 mm in diameter, distributed across the left upper abdomen and wrapping around to the left back. The remainder of the physical examination was unremarkable; axillary freckles, café au lait macules, and Lisch nodules were not observed.

Results of a biopsy of a nodule were consistent with a neurofibroma. The patient received a diagnosis of segmental neurofibromatosis, a variant of neurofibromatosis characterized by neurofibromas or café au lait macules (or both) that are confined to one body segment.

Segmental neurofibromatosis results from a postzygotic mutation in the NF1 gene, leading to somatic mosaicism.

The patient was scheduled for annual follow-up for surveillance of the nodules and any conditions that may be associated with neurofibromatosis. Because she has remained free from systemic complications of neurofibromatosis since birth, no specific treatment has been pursued. Her parents were offered genetic counseling on her behalf.