Intramedullary melanocytoma of thoracic spine: A rare case report

Abstract

Melanocytomas are present in leptomeninges and arise from neural crest during early embryonic development. They are a rare entity and usually occur in the thoracic spine and infratentorial region. We report a 32-year-old female with meningeal melanocytoma of D9-10. Magnetic resonance imaging revealed an intramedullary spinal tumor at D9-D10. Intraoperatively, the tumor was greyish-black in color with moderate vascularity, and was adherent to the cord. The clinical differential diagnoses included cavernoma and melanocytoma. On microscopic examination, the lesion showed sheets of cells with marked pigment deposition, which was obscuring the cellular morphology. The pigment was confirmed to be melanin by Masson's Fontana stain. Immunohistochemistry was performed, which showed positivity for HMB-45, S-100, Vimentin and Melan-A. The cells were negative for cytokeratin, epithelial membrane antigen, Glial fibrillary acidic protein and neuron-specific enolase. Mib-1 labeling index was less than 1%. In view of the lack of nuclear atypia, mitoses, necrosis and low Mib-1-labeling index along with immunohistochemistry profile, the diagnosis of Melanocytoma was made. Melanocytomas are rare pigmented tumors of the spinal cord and posterior cranial fossa. They are benign in nature, but can also be locally aggressive. Melanocytic lesions of the nervous system are to be differentiated from metastatic melanomas and also tumors showing melanin pigment deposition like schwanomma, paraganglioma, medulloblastoma and various gliomas.

S-100-negative, GNA11 mutation-positive intramedullary meningeal melanocytoma of the thoracic spine: A radiographic challenge and histologic anomaly

“…Melanocytoma is a rare primary spinal tumor with an annual incidence of 1/10 million, representing <0.1% of all CNS tumors. [ 7 ] The majority of these tumors arise in the intradural extramedullary compartment. [ 7 ] Intramedullary cases, such as this one, are exceedingly rare, with <30 cases reported in literature.…”

Spinal meningeal melanocytoma in a 5-year-old child: a case report and review of literature

“…As for clinical presentation, our case had only a 4-month history of non-radiating low back pain with no radiculopathy or sphincter affection. In literature, the most common feature was radiculopathy, either pain or heaviness followed by back pain and sphincter affection (Czarnecki et al 1997 ; Hou et al 2012 ; Yang et al 2016 ; Dorwal et al 2014 ; Sen et al 2011 ).…”

Subcutaneous melanocytoma mimicking a lipoma: a rare presentation of a rare neoplasm with histological, immunohistochemical, cytogenetic and molecular characterization

“…They can be further characterized as congenital and acquired. Congenital blue nevi: nevus of Ota and nevus of Ito have been associated with leptomeningeal neoplasms including melanocytomas . Acquired blue nevi generally involve the skin and present as flat or dome‐shaped pigmented lesions, although few case reports of cellular blue nevus with SC nodules have been reported .…”

“…After Limar and Tio described melanocytomas for the first time in 1972, there have been several publications, mostly case reports of melanocytomas occurring mainly through the neuroaxis. In children and young adults, meningeal melanocytomas could be related to neurocutaneous melanosis (NCM) . The highest concentration of melanocytes in the leptomeninges is usually found at the ventro‐lateral surfaces of the medulla oblongata and around the upper part of the spinal cord .…”

“…Melanocytomas usually present as intradural extramedullary masses that are often attached to nerve roots in the cervical or thoracic region . However, supratentorial, intramedullary and intraparenchymal CNS melanocytomas have been reported in the literature . Melanocytomas harbor characteristic mutually exclusive GNAQ/GNA11 mutations in closely related GTPases: Gα q and Gα 11.…”