Primary solitary melanoma of the cerebral meninges (a rare case from the practice of pathologist)

Background. Intracranial malignant melanomas are divided into primary and secondary. Secondary intracranial melanomas are metastatic, aggressive, and constitute the third most common group of metastatic brain tumors in adults. However, primary intracranial malignant melanoma (PIMM) is a rare tumor that originate from leptomeningeal melanocytes and accounts for 1% of all melanomas and 0.07% of malignant brain tumors. Objective. By the example of a medical case to attract attention and raise the awareness of pathologists concerning a rare localization of solitary malignant melanoma arising from the leptomeningeal membrane of the cerebellum. Methods. Pathomorphological examination of the primary solitary melanoma of cerebellum meninges using histological methods. Results. Pathomorphological examination of tissue from the tumor in the right cerebellar hemisphere, obtained during autopsy of a 66-year-old patient, showed that neoplasm is composed of polymorphic spindle-shaped cells with hyperchromic nuclei, a large number of pathological mitoses, the presence of dense intracytoplasmic deposits of black-brown pigment granules, foci of hemorrhages and necrosis, and invasion into the cerebellar tissue and intracerebellar vessels. Taking into account the absence of pigmented neoplasms of other locations, the presence of a pigmented tumor in the cerebellum, which is associated with the soft meninges, and a negative Perl’s reaction, the following pathological diagnosis was formulated: “Primary solitary melanoma of the soft meninges of the cerebellum with ingrowth into the cerebellar tissue and with foci of necrosis, complicated by edema-swelling of the brain tissue with dislocation of the brainstem”. Conclusion. The presented clinical case shows that, despite the significant difficulties in the intravital diagnostics of PIMM, adequate oncological alertness and careful examination of patients with similar clinical manifestations with the involvement of specialists of other profiles and MRI examination in the diagnostic process should be maintained in clinical practice.