What Tactics Should a Surgeon Choose to Treat a Black Extracerebral Tumor? A Case Report of Psammomatous Melanotic Schwannoma of the Meckel Cave and Literature Review

• Published in: World neurosurgery 2018-08, Vol.116, p.337-342
• Main Authors: Moisak, Galina I., Matsko, Dmitry E., Chernov, Sergey V., Dmitriev, Aleksandr B., Amelin, Mikhail E., Zhelbunova, Elena A., Chernov, Mikhail F., Rzaev, Jamil A.
• Format: Article
• Language: English
• Subjects: Melanin-containing tumor; Melanotic schwannoma; Psammomatous schwannoma; Tumor of Meckel cave
• ISSN: 1878-8750; 1878-8769
• DOI: 10.1016/j.wneu.2018.04.153

Neoplasms located in the Meckel cave account for 0.2%–0.5% of all intracranial tumors. This area is the site of many types of pathologic lesions, most often trigeminal nerve schwannomas and meningiomas. Melanin-containing tumors are rare in this area. These tumor types can be suspected if the magnetic resonance characteristics of a tumor has some differences in comparison with other types of central nervous system neoplasms. In fact, differential diagnosis of melanotic tumors is based mainly on the histopathologic criteria and immunohistochemical profile. This article presents a case report of melanotic schwannoma of the Meckel cave and a literature review of the problem. A 23-year-old man underwent a 2-stage surgery for a dumbbell pigmented mass lesion located in the Meckel cave. No signs of recurrence were seen on follow-up magnetic resonance imaging (MRI) 3.5 years after the operation. Melanin-containing tumor can be suspected in the presence of radiologic characteristics, such as a hyperintense MRI signal on T1-weighted images and a hypointense signal on T2-weighted images. If a black extracerebral tumor is detected, the main course of surgical treatment is maximal excision despite it possibly being a malignant melanoma and the temptation to perform partial resection because of an unfavorable prognosis. Chemotherapy can be justified in the presence of an aggressive melanotic schwannoma. •Hyperintense MRI signal on T1 and hypointense on T2 can help to suppose the presence of melanin-containing tumor.•The final diagnosis between types of melanotic tumor is based on histopathologic criteria and immunohistochemical profile.•Complete surgical resections of melanin-containing tumors of Meckel's cave are associated with better outcomes.•Melanin-containing tumors can show clinical aggressive behavior, and malignant transformation.•Gamma-knife surgery, radiotherapy, and chemotherapy can be used in cases of incomplete tumor resection or malignancy features.