Bilateral Neurofibromas of the Nipple-Areolar Complex: A Case Report and Approach to Diagnosis.

Neurofibromatosis type 1 is an autosomal dominant condition which can manifest as multiple neurofibromas within subcutaneous tissue. Neurofibromas of the breast are rare and most often encountered on the nipple-areolar complexes. A 33-year-old woman presented with large, bilateral, fleshy, skin tags of the nipple-areolar complexes. She underwent bilateral diagnostic excision of the lesions and macroscopically, both nipple specimens displaying polypoid lesions. Histological examination showed bilateral neurofibromas comprising skin with underlying dermal proliferation of bland spindle shaped cells with wavy nuclei. Immunohistochemistry confirmed the spindle cell proliferation to be neural in origin; positive for S100 and neurofilament and negative for cytokeratins. This was associated with florid smooth muscle proliferation. This case demonstrates a rare presentation of nipple-areolar neurofibroma occurring within the skin and nipple parenchyma. Our report considers the differential diagnoses of spindle cell proliferation within the dermis and subcutis of the breast and also other deeper breast spindle cell lesions that may involve the nipple. It aims to provide an approach to diagnosing these lesions examining the literature surrounding breast neurofibromas.