Abstract
Neurofibromatosis type one (NF1) is a relatively common genetic disorder, however, it is rare to see in pregnancy. There are few case reports detailing a link between increasing tumor size in pregnant patients with NF1 likely due to the increase in hormones. However, some neurofibromas, like the plexiform, can undergo malignant degeneration into aggressive malignant peripheral nerve sheath tumors (MPNST). Any patient with NF1 should undergo a prompt evaluation and biopsy of a plexiform neurofibroma if it starts to change in size or consistency. Due to the increased risk of malignancy in NF1 patients and the poor survival rates in MPNST, it should never be assumed that tumors enlarging in pregnancy are due to hormones. The case below details the enlargement of a plexiform neurofibroma on a 21-year-old gravida two parity one female at 28 weeks with NF1.