A Splenic IgG4+ Sclerosing Angiomatoid Nodular Transformation (SANT) Treated by Hemisplenectomy: A Radiologic, Histochemical, and Immunohistochemical Study

Introduction: Sclerosing angiomatoid nodular transformation (SANT) is a rare benign lesion of unknown origin for which total splenectomy is the standard treatment. Case Presentation: A 54-year-old man with a history of recurrent pancreatitis, bicuspid aortic valve, and aortic dissection underwent abdominal ultrasound, Computed tomography and magnetic resonance imaging, which revealed a 6-cm hypoechoic splenic mass diagnosed as cavernous hemangioma. Owing to his relevant past history, he was considered eligible for emisplenectomy and not for total excision, which is associated with long-term risks, especially infections. Results: Histologic examination revealed several nodules of varying size separated by sclerotic stroma with scattered inflammatory cells rich in IgG4+ in a background of splenic red pulp. Immunohistochemical stains showed a characteristic panel for CD34, CD31, and CD8. Conclusions: The diagnosis of SANT should be considered in any patient presenting with a splenic lesion containing an angiomatoid or inflammatory component. The only method able to establish a correct diagnosis is histologic and immunohistochemical evaluation. Complete splenectomy is generally considered the best approach. However, if the patient is at high risk of infection and localization of the lesion allows for selective devascularization of the affected part of the spleen, the lesion could be removed by hemisplenectomy. In some patients SANT is related to high blood levels of IgG4. Thus, corticosteroids might be useful for treating IgG4+ SANT and for preventing other IgG4-related diseases.