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. xanthoma, lo fibrous xant h~m a ,~ xanthogranuloma, mast cell granuloma," and even plasma cell tumor.' While these multiple designations refer to pathogenesis and/or a predominant histologic appearance of a single entity, the benign, nonneoplastic character of the lesion has to be recognized since it can be confused with a true neoplasm both clinically and pathologically.Most of the cases have occurred in the lung and extrapulmonary lesions have been rare. Although a few cases were noted in the liver,lg stomach, '3 and peritoneal and retroperitoneal spaces,31 no previous case has been reported as plasma cell granuloma in the meninges. T h e purpose of this investigation is to describe such a From the Clinical Laboratory and Neurosurgical Division, Koshigaya City Hospital, Saitama-ken, Japan. "tumor" presenting itself as a n intradural and extramedullary mass in the cervical spinal cord and to discuss some differential diagnoses.
CASE REPORTA 37-year-old ,Japanese man, a leatherette salesman, was admitted to the Koshigaya City Hospital because of weakness and sensory deficiency in the extremities. He had been well until a year prior to the admission when he developed paresthesia and progressive weakness of the left hand with subsequent involvement of the left lower extremity and right hand as well. There was no nausea, back pain or urinary disturbance, however. Upon admission the neurologic examination revealed hyperactive left tendon reflexes with positive Babinski reflex and bilateral decrease of pain, touch, and vibratory sensation below the level of C6. The extremities showed weakness, prominent in the left side. A lumbar puncture revealed a normal opening pressure but absence of Queckenstedt sign, 49 cells/mm3 (mostly lymphocytes), and elevated CSF protein (380 mg/100 ml). Myelography showed a nodular defect at C4 to C5 level with deviation of the spinal cord to the right (Fig. 1). All the other laboratory findings were negative including normal serum levels of gamma globulin and of lipids and negative serological tests for syphilis. At laminectomy the meningeal incision demonstrated an oval, extramedullary mass in the left posterior angle between the third and fourth posterior nerve roots, compressing the cervical spinal cord. However, there was no adhesion between the mas...