A rare case of lymphoplasmacyte-rich meningioma observed in a young girl is reported. The first clinical manifestations of the disease were seizures. Neuroradiological images favored the existence of a meningioma. Abnormalities in the patient's blood chemistry, principally including hypergammaglobulinemia and inflammatory syndrome, were associated with the disease. The tumor was histologically confirmed as meningioma with massive infiltrates of type B lymphocytes. The pathophysiology of the conspicuous lymphoplasmacyte infiltrates, responsible for peripheral blood abnormalities, has remained poorly understood. Alternative diagnostic hypotheses of masses that mimic this type of meningioma are discussed.