Immunohistochemical study of multiple inflammatory pseudotumors with both brain and spinal cord involvement--case report.

A 55-year-old man presented with a rare case of both intracranial and intraspinal inflammatory pseudotumors manifesting as progressive motor weakness in his lower extremities. Magnetic resonance imaging revealed a 24-mm diameter tumor-like lesion in the left parietal lobe and an intramedullary 24-mm diameter lesion at the C7 and T1 levels of the spinal cord. These lesions were resected by sequential operations. Histological examination of the resected lesions revealed the presence of excessive collagen fibers infiltrated with polyclonal lymphocytes and plasma cells, and the diagnosis was inflammatory pseudotumor. Immunohistochemical staining with anti-immunoglobulin G4 (IgG4) antibody found no accumulation of IgG4-positive cells. The serum IgG4 level was normal. Thus, this case did not meet the criteria for IgG4-related disease.