Sclerosing Angiomatoid Nodular Transformation of The Spleen: A report of a rare entity

Abstract

Abstract Introduction/Objective Sclerosing angiomatoid nodular transformation (SANT) is a benign vascular lesion of spleen with uncertain etiology. It predominately affects women between 30 to 60 years of age. Clinically, it is asymptomatic or can cause abdominal pain, but usually discovered incidentally on imaging, which can identify a mass but may not provide a definitive diagnosis. In uncertain vascular lesions, there is always a risk of spontaneous rupture of large vessels and potential for spreading malignancy. Hence, the final diagnosis is rendered on microscopy after splenectomy Methods/Case Report A middle age female came to clinic complaining of abdominal pain. Radiology showed solid splenic mass and the patient underwent splenectomy. Gross examination showed a 3 cm white firm mass with focal hemorrhage. Microscopy revealed multiple nodules of variable sizes surrounded by fibrosclerotic stroma. The nodules showed round to slit-like vascular spaces with numerous red blood cells. The internodular stroma consisted of dense fibrous tissue with scattered plump myofibroblasts and lymphoplasmacytic cells. These distinctive features lead to the diagnosis of SANT Results (if a Case Study enter NA) SANT possessed characteristic histologic features with distinctive immunohistochemistry (IHC). IHC reveals three different types of vessels within the nodules: 1. Small veins (CD34- CD31+ CD8-); 2. Sinusoids (CD34- CD31+ CD8+); and 3. Capillaries (CD34+ CD31+ CD8-). All 3 vessels are negative for CD21/CD35 and CD68. Hemangioma and littoral cell angioma are two frequent vascular tumors in the spleen that should be differentiated. Both lesions lack microscopic features of SANT and have only a single type of vessels. The vessels in hemangioma are (CD31+ CD34+ CD8-); while in littoral cell angioma they are (CD31+ CD34- CD8- CD21+ CD68+) Conclusion There are no specific clinical or radiologic findings for SANT. It is important to recognize these characteristic features and to differentiate it from other benign and malignant lesions, such as angiosarcoma. A thorough histopathologic examination and IHC are helpful to make the correct diagnosis