Sclerosing angiomatoid nodular transformation of the spleen: A case report.

Sclerosing angiomatoid nodular transformation is a benign vascular pathology of the spleen, developed from the red pulp, of unknown etiology; it is postulated that it may be related to IgG4 disease and Epstein-Barr virus infection. Most cases are asymptomatic, constituting incidental findings in imaging studies. We present a 41-year-old male patient with a history of thyroidectomy for papillary carcinoma who consulted for fever, received symptomatic treatment and performed a computed tomography of the abdomen for nonspecific abdominal symptoms, the same evidence in the lower pole of the spleen a solid-looking image with faint Peripheral enhancement with contrast, measures 62x 52x51 mm. A splenectomy measuring 14x 11x4 cm and weighing 284 grams was performed, identifying a solid, well-defined nodular formation, with a central fibrous-looking area, with whitish tracts that delimited purplish areas. Microscopy: rounded angiomatoid-like coalescing nodules, with vascular proliferation lined by endothelial cells without atypia, interspersed with spindle cells, infiltrated by lymphocytes and macrophages. The stroma between the nodules shows myofibroblastic proliferation with lymphocytes, plasma cells, and siderophages. Immunohistochemistry: positive labeling in vessels for CD34 and CD31, positive sectors for CD8 and negative for CD34. One IgG4 positive cell per high power field. The study for Epstein-Barr by Polymesara Chain Reaction was negative. For the diagnosis, the imaging studies are nonspecific, so the diagnostic confirmation is given by the histopathological study. Splenectomy is curative with no reported cases of malignant transformation or recurrence to date. There are no known risk factors and no triggering factors have been proven, except the association of cases with IgG4 and Ebstein-Barr virus. As it is a recently described pathological entity, it is necessary to collect large series and review our files, reevaluating some of its differential diagnoses to achieve a better understanding of it.