Plasma cell granulomas are a rare form of idiopathic inflammatory pseudotumors often characterized by non-neoplastic proliferation of plasma cells, clinically mimicking a neoplastic process. Pseudotumors of the central nervous system, however, are exceptional and rare. The authors describe a 14-year-old girl with a mass lesion extending medially along the cavernous sinus into the right middle cranial fossa and pterygopalatine and infratemporal fossae. The authors review the current literature and discuss successful treatment with methotrexate and 6-mercaptopurine after recurrence of disease following radiation therapy and steroids.