The role of immunohistochemistry in lymphoplasmacyte-rich meningioma

Abstract

Objective: Lymphoplasmacyte-rich meningioma is a very rare subtype of benign meningioma, which is characterized by prominent inflammatory cell infiltration with sparse meningothelial component. The incidence is less than 1% of all meningiomas. We present a case of 45-year-old male without any systemic hematologic abnormalities. Material and Methods: The patient was admitted to the University Clinic of Neurosurgery with headache, confusion, disorientation, nausea and vomiting. Neurological examination and complete blood count were normal. The MRI revealed isodense, contrast-enhanced dural mass in the right frontal parasagital region. Total tumorectomy was done and gross examination showed oval, well-circumsribed tumor with diameter of 4 cm. Results: Microscopic analysis showed neoplasm composed of rare nests of meningothelial cells surrounded by extensive lymphocytic and plasma cell infiltrate, separated by proliferated collagenous connective tissue bands. The meningothelial cells had round to oval nuclei without clear cytoplasmic borders. Immunohistochemistry showed positive signal for EMA, PR, CD3, CD4, CD20, LCA, CD79alfa, and Bcl2; focal positive signal for CD138, IgA, IgD, IgG, IgM, kappa, lambda and negative signal for CD34, CD10,CD23. The proliferative index for Ki-67 was low (4%). Conclusions: Immunohistochemical analysis had a crucial diagnostic role in differentiating this rare tumor subtype from intracranial inflammatory process.