Inflammatory pseudotumor of the spleen associated with a cavernous hemangioma diagnosed at intra-operative cytology: report of a case and review of literature.

This report presents a case of a 40 year old Caucasian female with a 15 cm inflammatory pseudotumor (IPT) of the spleen with associated areas of splenic hemangioma of the cavernous type. Abdominal CT showed a largely fatty splenic mass with enhancing septations, and scattered calcifications, and a small density in the liver. Grossly, the splenic lesion showed a lobulated cut surface with areas of myxoid change, necrosis, hemorrhage and cystic softening. The diagnosis of IPT was suggested at intraoperative consultation using cytologic smears and was, subsequently confirmed on permanent sections. Histologically, the lesion consisted of a densely collagenized spindle cell stroma with patchy aggregates of lymphocytes and plasma cells, and scattered foci showing hemosiderin-laden macrophages extracellular calcium deposits and osseous metaplasia. The stromal spindle cells were immuoreactive for smooth muscle actin and vimentin confirming their myofibroblastic phenotype. There were extensive areas of infarction within the mass. The patient, however, remained asymptomatic preoperatively. Histologic analysis in this case raises the possibility that low grade, perhaps repetitive, trauma to the hemangioma may have resulted in intralesional hemorrhages which, through a process of organization, may have evolved into this sizable inflammatory pseudotumor. In addition, this report reviews the current literature on the clinical significance and presentation, morphologic and immunohistochemical findings, prognosis, differential diagnosis, pathogenesis and therapy of the splenic IPT.