INFLAMMATORY PSEUDOTUMOR OF THE SPLEEN - A CLINICOPATHOLOGICAL AND IMMUNOPHENOTYPIC STUDY OF 8 CASES

We report the clinical, pathologic, and immunophenotypic findings of i nflammatory pseudotumors of the spleen in eight patients. The primary importance of recognizing these uncommonly found lesions is to disting uish them from malignant lymphoma, which splenic inflammatory pseudotu mors may mimic clinically and radiologically. Grossly, the splenic inf lammatory pseudotumors in this study ranged from 0.5 to 11.5 cm. One c ase was multinodular, and seven lesions were solitary. In general, the size of the lesion correlated with the presence of symptoms. The smal ler lesions were usually incidental findings, discovered as part of th e workup of idiopathic thrombocytopenic purpura (three cases), during staging for Hodgkin's disease (one case), or at autopsy (one case). Mi croscopically, the lesions were composed of a variable mixture of infl ammatory cells admixed within a spindle cell proliferation. Small, cyt ologically normal lymphocytes and plasma cells were constant features, in a variable mixture, with neutrophilic and eosinophilic leukocytes present in some cases. Coagulative necrosis was located centrally in s ix lesions; neutrophilic leukocytes were correlated with the presence of necrosis. The presence of necrosis did not correlate with the prese nce of symptoms. Immunohistochemical studies revealed that the small l ymphocytes present were predominantly T cells. Histiocytes and polytyp ic plasma cells were also numerous, whereas B cells were infrequent. I nflammatory pseudotumors of the spleen are benign lesions. The clinica l follow-up for the seven patients in this study who underwent splenec tomy showed no evidence of recurrence or subsequent development of a h ematopoietic neoplasm, with a median follow-up of 18 months (range, 3 to 135 months).