Sclerosing angiomatoid nodular transformation (SANT) of the spleen: A case report on CT and MRI.

Solid tumors of the spleen are rare, with an incidence of 0.007% in all operating and autopsy specimens. In terms of microscopic structure and function, the spleen consists of two parts: the white pulp, which plays an important role in the immune system and the red pulp, which filters the blood.Primary splenic neoplasms can be classified into lymphoid neoplasms arising from the white pulp, and vascular neoplasms which arise from the red pulp.Primary tumors arising from vascular elements include benign lesions such as hemangioma, lymphangioma and hamartoma, intermediate lesions such as hemangioendothelioma, hemangiopericytoma and littoral cell angioma as well as the frankly malignant hemangiosarcoma.It is usually difficult to distinguish a benign from a malignant lesion with preoperative imaging studies and cytological exam by fine-needle aspiration (FNA), that is not easily obtained because of the risk of bleeding.Therefore a splenectomy should be necessary for a definitive diagnosis of splenic tumors.Martel and all for the first time described the sclerosing angiomatoid nodular transformation (SANT), like a vascular lesion of the spleen, with benign clinical course consisting by altered red pulp tissue that has been entrapped by a non-neoplastic stromal proliferative process.We describe a rare case of benign splenic mass documented with FDG/PET-CT (referred as equivocal), CT and MRI.