[Inflammatory pseudotumor of the spleen. An old concept with many questions]

Inflammatory pseudotumor of spleen is an infrequent benign condition. It is difficult to differentiate, on a clinical and radiological basis, from haematologic neoplasms, granulomatous diseases as sarcoidosis and splenic hamartoma. Sometimes can be an incidental finding. Two women, aged 72 years, are presented. On the first case the sympthons mi micked a malignant disease. The second one was an incidental finding in a routine study for cholecystitis. Histological and immunohistochemical study showed a polymorphic cellular population including plasma cell, lymphoid cells, histiocytes, eosinophils and spindle cells, showing a reactive benign character. Plasma cells presented light chains polyclonality. Lymphoid cells were mature and with T inmunophenotype. Spindle cells were focally positive for muscle spe-cific actin and vimentine. In the first case, ultraestructural study showed myofibroblast morphology on the stromal spindle cells. Like many other authors have already postulated, immunohistochemical and ultraestructural findings would corroborate the mesenchymal reactive and benign nature of this type of lesions.