Malignant Melanotic Nerve Sheath Tumor of the Parotid Gland: A Case Report and Literature Review

Abstract

Malignant melanotic nerve sheath tumor (MMNST) is a rare and aggressive peripheral nerve sheath tumor of Schwann cell origin that produces differentiated melanin and is clinically misdiagnosed as malignant melanoma. MMNST is most commonly observed in middle-aged adults and is often found in the midline of the spinal nerve or in the peripheral nerve area. It often manifests itself as a localized mass and/or nervous system involvement. To date, no standard guidelines are available for the treatment of MMNST. Herein, we reported a new case of MMNST that occurred in the parotid gland and reviewed the literature for pathological reports on its association with the oral cavity.

18F-FDG PET/CT revealed sporadic schwannomatosis involving the lumbar spinal canal and both lower limbs: a case report

“…The lesion often exhibits prominent thick-walled blood vessels, along with frequent occurrences of mucoid degeneration, hemorrhage, and calcification within the tumor. Immunohistochemically, there was diffuse strong positive expression of S100 and SOX10 (23)(24)(25), focal positive expression of glial fibrillary acidic protein (GFAP) in some cases, focal keratin positivity in a few cases, while negative for melanocyte-specific markers HMB45 and melan-A (24,26). The patient underwent bilateral lower limb tumor resection and intraspinal tumor biopsy at the level of the first lumbar spine, which microscopically showed that these tumors were composed of Antoni A areas rich in spindle cells and Antoni B areas rich in mucoid substance.…”