Lymphoplasmacyte-Rich Meningioma With Atypical Angiomatous Feature and an Increased Deposition of IgG4-Positive Plasma Cells: An Unusual Case Report.

Lymphoplasmacyte-rich meningioma (LPRM) is an extremely rare variant of meningioma, and a small percentage of LPRM may be associated with IgG4-related disease. To date, the coexistence of 2 rare meningioma variants consisting of LPRM and angiomatous meningioma within one neoplasm has not been reported in the literature. A 56-year-old woman presented with episodes of frequent and severe epistaxis that began 4 months ago. Initial magnetic resonance imaging showed localized, heterogeneous, and intermediate to high signal lesion at the odontoid process and clivus. In subsequent magnetic resonance images, the mass grew to the posterior nasopharyngeal wall, and compression to the medulla, and a suspicious enhancement of both distal vertebral arteries became evident even though there was 3 times of partial resection over 17 years. The tumor showed regional and temporal heterogeneity, and atypical features such as mitoses and a high proliferative index were also identified in the area of angiomatous meningioma in addition to LPRM with an increased deposition of IgG4-positive plasma cells within the neoplasm.