Inflammatory pseudotumor of the spleen: report of a case.

A case of an inflammatory pseudotumor arising in the spleen of a 60-year-old Japanese male is described herein. This benign lesion is extremely rare, with only 12 cases, including our own, having been reported in the world literature. We preoperatively diagnosed the splenic tumor as a metastasis, due to the coexistance of advanced stage carcinoma in the sigmoid colon. However, after splenectomy, histopathological examination of the mass revealed an inflammatory process. Inflammatory pseudotumors often pose diagnostic difficulties because the clinical and radiologic findings are suggestive of malignancy. The clinical and pathological features of cases previously reported are reviewed following the presentation of this case.