Expanded Radiologic Characterization and Long-Term Imaging Follow-Up of Sclerosing Angiomatoid Nodular Transformation (SANT): A Case Report

Sclerosing angiomatoid nodular transformation (SANT) is an uncommon, non-malignant vascular lesion of the spleen that can resemble malignant lesions during imaging studies. Histologically, the spleen comprises two parts: the red pulp, which acts as a blood filter, and the white pulp, which plays a crucial role in immunity. Primary splenic neoplasms are classified into lymphoid neoplasms, which arise from the white pulp, and vascular neoplasms, which arise from the red pulp. Lesions arising from vascular elements include benign lesions, such as hemangioma, hamartoma, and SANT, as well as intermediate or variable lesions, including hemangioendothelioma, hemangiopericytoma, and littoral cell angioma. Lastly, there are malignant lesions such as angiosarcoma. This report presents the case of a patient with a solitary, well-defined splenic mass on abdominal imaging. The patient had recently been diagnosed with acute hepatitis B and was in the cholestatic phase at the time the splenic lesion was identified. He had been initiated on tenofovir therapy. The lesion demonstrated characteristic radiological features of SANT. Histopathological examination confirmed the diagnosis of SANT. This case highlights the importance of considering SANT in the differential diagnosis of splenic masses, particularly when imaging findings are inconclusive. Early recognition and appropriate management can prevent unnecessary invasive procedures and psychological trauma. This report provides an expanded radiologic perspective and long-term imaging follow-up of a case previously described from a clinical viewpoint.