Extramedullary malignant melanotic schwannoma of the spine: Case report and an up to date systematic review of the literature

Abstract

Background Melanotic schwannoma is a rare variant of schwannoma. Extramedullary melanotic schwannoma originates in the vicinity of nerve roots mimicking other intervertebral disc disorders. Therefore, T1 and T2-weighted MRI sequences become an essential tool for diagnosis. Aside from case reports, no large studies exist to provide consensus on the signal intensities in T1 and T2-weighted MR imaging. Moreover, no clear evidence is available to delineate prognosis. Here, a case report is presented together with a subsequent systematic review of the literature regarding this rare entity. Case description A 45-year old female presented with a one-year history of insidious onset of neck pain and paraesthesia. Magnetic resonance imaging confirmed an extramedullary lesion along the C6 nerve root with T1-weighted hyperintensity and T2-weighted hypointensity. Despite two surgical decompressions and adjuvant immunotherapy, the patient unfortunately passed away due to metastatic progression. Discussion According to the systematic review conducted, in over half of the cases of extramedullary melanotic schwannoma, there is local reoccurrence and/or distal metastasis. Moreover, in 64.7% and 70.6% of the cases, the T1-weighted image of the lesion appears hyperintense and hypointense on a T2-weighted image, respectively. It is an aggressive variant of schwannoma, one of the most commonly observed extramedullary tumours presenting to neurosurgical practice. Conclusion Our results highlight that specific T1 and T2-weighted imaging findings can provide valuable information, enabling early suspicion, influencing the surgical aims and strategy and the timely commencement of relevant immunotherapy. Considering the poor prognosis, early adjuvant therapy with other modalities should be considered.

Leptomeningeal dissemination of a malignant melanotic nerve sheath tumor: A case report and review of the literature

“…Approximately 200 cases have been reported in the literature since the first identified case published in 1931 by Millar, who described the lesion as a “malignant melanotic tumor of the ganglion cells,”[ 4 ] with fewer than 70 of these lesions localized to the spine. [ 5 ] These lesions may be separated into psammomatous and non-psammomatous subtypes. Non-psammomatous lesions appear to arise sporadically, while psammomatous subtypes are considered to be part of the Carney complex, characterized by the presence of cutaneous lesions, endocrine tumors, and cardiac myxomas.…”

“…Malignant melanotic nerve sheath tumors (MMNSTs) of the spine are rare, and fewer than 70 cases are described in the literature. [ 5 ] According to the 5 th Edition of the WHO classification of soft tissue and bone lesions, these most commonly affect the dorsal nerve roots but can also impact the entire neuroaxis and the gastrointestinal tract. Despite a relatively benign histological appearance, they exhibit high local recurrence rates and/or metastases.…”

Immunotherapeutic treatments for spinal and peripheral nerve tumors: a primer

“…Solomou et al reported the use of multiple immunotherapeutics in the management of a patient with advanced melanotic spinal schwannoma. 39 They described a case of a dumbbell-shaped lesion with intradural and extradural components in the cervical spine along the C6 nerve root. The patient underwent 2 surgical procedures and received combination immunotherapy, including nivolumab (programmed cell death protein 1 [PD-1] death-ligand receptor), ipilimumab (cytotoxic T-lymphocyte antigen 4 [CTLA4]), and denosumab (receptor activator of nuclear factor kappa b ligand antibodies), as these therapies have previously shown efficacy in treatment of primary melanoma.…”

“…The patient underwent 2 surgical procedures and received combination immunotherapy, including nivolumab (programmed cell death protein 1 [PD-1] death-ligand receptor), ipilimumab (cytotoxic T-lymphocyte antigen 4 [CTLA4]), and denosumab (receptor activator of nuclear factor kappa b ligand antibodies), as these therapies have previously shown efficacy in treatment of primary melanoma. 39 Unfortunately, this aggressive immunotherapy combination was ineffective, and the patient was subsequently readmitted with respiratory complications and died. 39 Another report by Sahay et al described 7 cases of melanotic spinal schwannoma occurring in the cranium or spinal cord.…”

“…39 Unfortunately, this aggressive immunotherapy combination was ineffective, and the patient was subsequently readmitted with respiratory complications and died. 39 Another report by Sahay et al described 7 cases of melanotic spinal schwannoma occurring in the cranium or spinal cord. 40 Four of these cases originated in the spine, in which 1 patient received immunotherapy following resection of a lumbar tumor.…”