Plasma cell granuloma (inflammatory pseudotumor) of the spinal cord meninges: report of a case.

A case of plasma cell granuloma (inflammatory pseudotumor) arising in the meninges of cervical spinal cord of a 37-year-old Japanese man is presented. The diagnosis was made by analogy with the similar lesions known in the lung. Its histology was characterized by infiltration of three kinds of cells; histiocytes with slight epithelioid appearance, plasma cells with numerous Russell bodies, and lymphocytes. Electron microscopy of the formalin-fixed tissue was useful for the identification of these cells, particularly of histiocytes. Although extrapulmonary plasma cell granulomas have been reported, this is the first case, to our knowledge, of this type "tumor" in the spinal cord meninges. Differential diagnoses have been briefly discussed.