Intracranial plasma cell granuloma.

Plasma cell granulomas (PCGs) are benign, inflammatory masses of unknown etiology composed of polyclonal mature plasma and lymphoid cells. The lung is their most common location, and occurrence within the cranial cavity is extremely rare. We report the case of an 11-year-old girl who presented with seizures and was diagnosed as having a dural-based right frontal tumor that extended toward the sagittal sinus and the falx. The lesion was totally excised, together with the abnormal dura. A limited cortical excision was also performed using electrocorticographic guidance. Histopathologic diagnosis of intracranial plasma cell granuloma was reached after extensive immunohistochemical tests and electron microscopy. This is the third case of PCG with description of changes in the neighboring cerebral tissue. Although PCGs are well-circumscribed lesions, lymphoplasmocytic inflammation, neuronal loss, and reactive gliosis occur within the adjacent cortex. Disturbed cortical lamination, as we have observed, appears to be a histological finding that has not been described previously.