Plasma-cell granuloma of the fourth ventricle. Case report.

The case is presented of a 36-year-old woman with a plasma-cell granuloma arising in the fourth ventricle. The mass appeared on computerized tomography as a well circumscribed area of slightly high density that was markedly enhanced with contrast medium. Microscopic examination showed a mixed-cell population with a predominance of plasma cells, and the tumor was characterized immunohistochemically by polyclonal plasma-cell proliferation.