Abstract

Vulvar peripheral nerve sheath tumors (PNST) are rare, neurofibroma being the most common, followed by schwannoma, and malignant peripheral nerve sheath tumor (MPNST). As the literature is predominantly composed of single cases or small series, the aim of this study was to evaluate the clinicopathologic features of a series of vulvar PNST, including clinical outcomes. This series included 23 vulvar tumors from 21 patients. Available pathologic material was reviewed. Additional clinical and outcomes data was pooled from the electronic medical record. The tumor types were neurofibroma (NF) (17, of which 3 were plexiform NF and 1 was myxoid NF) and schwannoma (6, of which 1 was plexiform schwannoma and 3 were granular cell schwannomas). NF occurred in 3 patients with neurofibromatosis type 1 (NF1). The patient with the plexiform schwannoma had neurofibromatosis type 2 (NF2) whereas none of the patients with typical schwannoma had NF2. Median age at time of diagnosis was 49 years (range 12.5 – 79.3). All patients with either NF1 or NF2 had other PNST in addition to the vulvar lesion. Median size of vulvar tumors was 1.1 cm (range 0.5 – 6.2). Pathologic examination of the plexiform schwannoma showed Verocay bodies whereas the NF and plexiform NF showed a proliferation of spindled cells embedded within a collagenous background. Tumors extended to the specimen edges in most cases. Local recurrence occurred in 2/3 patients with NF1 (at 0.4 years and 2.9 years). None developed vulvar MPNST. All patients were alive at time of last follow-up without evidence of local disease (follow up range 2.7 – 7.7 years). A diagnosis of vulvar PNST should elicit clinical evaluation for the possibility of NF1 or NF2. Awareness of the potential for local recurrence, particularly for NF, is merited. Although our series did not include patients with transformation to MPNST, this possibility should also be considered in the setting of a recurrent tumor.

Financial Disclosure:
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