Inflammatory myofibroblastic tumor of the spleen: a case report and review of the literature

Inflammatory myofibroblastic tumor of the spleen (IMTS) is an extremely rare, intermediate malignant tumor with unclear etiology, and is most frequently detected incidentally. IMTS presents with nonspecific symptoms that pose a diagnostic challenge to clinicians or presents with the similar appearances to splenetic malignant neoplasms that pose a misdiagnose prior to surgery. Histopathology of the resected specimen remains the gold standard for diagnosing these rare splenic tumors. But these tumors may be misdiagnosed if pathologists are not familiar with the histologic pattern of their variations. In this paper we report a rare case of IMTS in a 55-year-old female admitted to the Xingtai People's Hospital affiliated to Hebei Medical University, with a mass of the spleen. The mass was identified incidentally two months ago and was initially diagnosed as a splenic lymphoma. The patient underwent laparoscopic splenectomy and the histologic study of the specimen revealed findings consistent with IMTS. Histological examination of the nodular growth revealed spindle cells in a hyalinized stroma with inflammatory infiltration of predominantly plasma cells and lymphocytes, coupled with lymphoid follicle structures. Immunohistochemical staining was performed to confirm the diagnosis of IMTS. Splenectomy is both diagnostic and curative for IMTS, and prognosis is generally favorable following the procedure. Our case report of IMTS adds to pathologists' knowledge of diagnosis. Meanwhile, the description and the review of features of IMTS, based on published cases, should help to improve the understanding and diagnosis level of this rare disease.