Abstract
Neurofibromatosis type 1 is an autosomal dominant disorder predisposing patients to plexiform neurofibromas, benign tumors with an 8%-13% lifetime risk of malignant transformation into malignant peripheral nerve sheath tumors (MPNSTs). MPNSTs are aggressive sarcomas with poor prognosis. We present the case of a 13-year-old neurofibromatosis type 1 patient with a large, pedunculated, scalp plexiform neurofibroma who underwent subtotal surgical excision to improve her appearance and ability to wear hats. The patient was treated preoperatively with selumetinib for size reduction, and the procedure was bloody. Pathology revealed that the neurofibroma had an intralesional high-grade MPNST. Margin status for the malignant component was inconclusive. Immunohistochemistry revealed loss of H3K27me3 expression, indicative of aggressive tumor biology. The patient underwent adjuvant chemotherapy followed by a re-excision of the surgical site, which showed no residual tumor.