RESUMO
Malignant peripheral nerve sheath tumors (MPNSTs) are malignant variants of peripheral nerve sheath tumors that develop at major or minor peripheral nerve branches or at the sheaths of peripheral nerve fibers. These tumors are derived from Schwann cells or pluripotent cells of a neural crest origin. Malignant tumors of the peripheral nerve sheath are most commonly seen in deeper soft tissues, and usually in the proximity of a nerve trunk. MPNSTs of the breast are very uncommon and they have rarely been reported on. We report here on a case of MPNST of the breast in a 59-year-old female who presented with a painless breast lump for two months. The excisional biopsy revealed a malignant peripheral nerve sheath tumor based on the microscopic findings and immunohistochemical staining. We performed wide excision of breast tissue around the biopsy site and thereafter the patient underwent radiation therapy. The patient remains well without signs of recurrence 1 year following surgery.