Multifocal meningeal melanocytoma: a new pathological entity or the result of leptomeningeal seeding?

Abstract

Meningeal melanocytoma is a rare benign CNS tumor derived from the leptomeningeal melanocytes. Although unusual, malignant transformation with leptomeningeal seeding into the brain or spinal cord may occur years after the initial diagnosis. The authors report a unique case of multifocal benign meningeal melanocytoma involving both cerebellopontine angles and the thoracic spinal cord, with associated diffuse leptomeningeal hyperpigmentation. They review the literature relevant to this topic and discuss the radiological and pathological features of this disease as well as its treatment options.

MR Imaging Findings of the Intraspinal Meningeal Melanocytoma: Correlation with Histopathologic Findings

“…The tumor occurs almost exclusively in the posterior fossa and spinal cord. 6,7,10,11 The annual incidence of MM is estimated to be 1 case per 10 million people, and women are vulnerable. 10 Our hospital has an extremely large collection area for patients from Guangdong province and 4 neighboring provinces.…”

“…2,4 These cells are present in the leptomeninges of healthy adults and may result in primary leptomeningeal pigmented tumors, including pigmented meningioma, malignant melanoma, MM, melanotic schwannoma, and melanoblastosis. 6,7 Malignant melanoma and MM are of the same origin and represent the malignant and benign ends of the tumor spectrum, respectively. 5 MM was first coined by Limas and Tio 3 in 1972.…”

Multiple spinal cord melanoma: case report with emphasis on the difficult preoperative diagnosis

“…Intermediate-grade melanocytic tumors are not easily classified as melanocytoma or melanoma as they present some histological features associated with aggressive behavior, and moreover, only sporadic cases have been reported in the literature (2,3). To the best of our knowledge, only two cases of multifocal primary melanocytic tumor have been reported in the literature (1,9). In this study, we present a case of multiple spinal cord melanoma located at the level of the cervical and upper thoracic vertebrae, and conduct a review of the pertinent literature.…”

“…Adjuvant radiation therapy and Gamma Knife radiosurgery have been shown to control tumor growth and improve outcome following partial resection (1, 12). Ali et al reported a case study of a 31-year-old patient presenting with a multifocal meningeal melanocytoma simultaneously affecting both cerebellopontine angles and the thoracic spinal cord, and exhibiting a remarkably aggressive clinical course and a poor prognosis (1). In this case study, we introduce a new entity, multiple intermediate-grade melanocytoma, which similarly appears to portend a poor prognosis.…”

“…The lesional cells were immunopositive for S100 protein and HMB-45, whereas no expression of epithelial membrane antigen was detected ( Figure 4A-D). The diagnosis based upon the pathological (1,9). The characteristics of these cases are summarized in Table I.…”