Melanotic meningioma

Last revised by Frank Gaillard on 24 Dec 2021

Melanotic meningiomas are a rare histological variant of metaplastic meningioma. This should not be confused with anaplastic meningiomas (grade 3) that may resemble malignant melanomas.

As only several dozen cases have been reported in the literature, no significant difference in prevalence has been found between genders/age groups.

Melanotic meningiomas arise from leptomeningeal melanocytes, small pigment cells found mostly in the meninges covering the ventrolateral surfaces of the medulla oblongata, posterior cranial fossa or Meckel cave 1,2.

Given the small number of reported cases it is difficult to determine the most characteristic appearance.

These tumors are most commonly isodense to grey matter, with variable enhancement 2.

Different signal intensities are probably correlated with the amount of melanin in the pigment cells. Possible causes of low signal intensity on T2-weighted sequences include decreased water content, paramagnetism, susceptibility effects or hemorrhage 5

  • T1: iso- or hyperintense 1,4
  • T2: hypo- or hyperintense
  • T1 C+: homogenous enhancement

Similar to other meningiomas the treatment of melanotic meningiomas is usually surgical excision, with complete tumor removal being the best therapeutic option (in terms of disease-free survival) 3.

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