Inflammatory Pseudotumor of the Spleen Masquerading as Splenic Malignancy.

Inflammatory pseudotumors (IPTs) of the spleen are extremely rare, benign tumors of unknown etiology, and are most frequently detected incidentally. We report a case of IPT of the spleen in a 19-year-old male, who presented to the Hamdard Institute of Medical Sciences and Research, New Delhi, with a history of pain and heaviness in the left hypochondrium. On clinical examination, splenomegaly was detected. Ultrasonography and contrast-enhanced computed tomography of the abdomen revealed an enlarged spleen with a mass lesion completely occupying the lower pole of the spleen. Therefore, a diagnosis of splenomegaly with a malignant splenic lesion was suggested. Open splenectomy was performed. On gross examination, a well-circumscribed nodular growth measuring 9 × 8 × 5 cm in diameter was seen on the lower pole of the spleen, which on cut section appeared tan white with foci of yellowish discoloration. Microscopic examination of the nodular growth revealed spindle cells in a hyalinized stroma with inflammatory infiltration of predominantly plasma cells and lymphocytes. On immunohistochemistry, the spindle cells were positive for smooth muscle actin. A diagnosis of IPT of the spleen was rendered following histopathology testing. Splenectomy is both diagnostic and curative for this rare entity, and prognosis is usually favorable following the procedure.