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Sclerosing angiomatoid nodular transformation of the spleen: A case report

Abstract:

Sclerosing angiomatoid nodular transformation is a benign vascular pathology of the spleen, developed from the red pulp. Its etiology is unknown, although it is suggested that it may be related to immunoglobulin four disease and Epstein-Barr virus infection. Most cases are asymp-tomatic, constituting incidental imaging findings. We present the case of a 41-year-old male patient with a history of thyroidectomy for papillary carcinoma who consulted for fever. He received symptomatic treatment, and an abdominal computed tomography scan was performed due to non-specific abdominal symptoms. The image showed a lesion of solid aspect, with faint peripheral contrast enhancement, measuring 62 by 52 by 51 millimeters in the lower pole of the spleen. Splenectomy was performed. The macroscopic study showed a 14 by 11 by 4 centime-ters spleen that weighed 284 grams. A solid, well delimited nodular formation with a central fi-brous area and whitish tracts dividing violaceous regions was identified. Microscopy showed round coalescent nodules of angiomatoid appearance, in which a slit-like vascular proliferation was lined by endothelial cells without atypia, interspersed with spindle cells and infiltrates of lymphocytes and macrophages. The stroma surrounding the nodules showed myofibroblastic proliferation with lymphocytes, plasmacytes, and siderophages. Regarding immunohistochemis-try, the vessels were CD34 9 (+) and CD31 (-), and some areas were CD8(+) and CD34 (-). One cell was positive for immunoglobulin 4 (IgG4) by high magnification field. The study for Epstein-Barr by polymerase chain reaction was negative. Imaging studies are non-specific to diagnose sclerosing angiomatoid nodular transformation, so the histopathological study is the gold standard. Splenectomy is curative, and there are no reported malignant transformation or recurrence cases. To date, risk factors are unknown, except for a suggested association with IgG4 and Epstein-Barr virus. As this entity is new, it is necessary to compile large series and review differentials of previous cases to achieve a higher understanding of the disease.