Sclerosing angiomatoid nodular transformation (SANT) is a peculiar splenic vascular lesion that is characterized by marked stromal sclerosis and the presence of plasma cells, which shares histopathological features associated with IgG4-related sclerosing disease. The cinicopathological features of 10 cases of SANT were reviewed and immunohistochemistry with IgG4 and IgG antibodies was performed. Nine other various splenic lesions served as controls. Five cases of SANT were found incidentally. Three cases of SANT had multiple tumors and five had associated abdominal disseminated calcifying fibrous tumors (CFT). IgG4+ plasma cells were found in all of the cases of SANT and in calcifying fibrous tumors. The densities of IgG4+ and IgG+ cells and the IgG4/IgG ratios were significantly higher in SANT than in control spleens (P= 0.001, 0.006, and 0.028, respectively). Serum IgG4 concentration was elevated in one case. In conclusion, SANT can occur either as a solitary or as multiple tumors. Frequent association with abdominal disseminated CFT simulating carcinomatosis was observed. A statistically significant number of IgG4+ plasma cells was found in all of the cases of SANT and the associated CFT. Whether they are related to the IgG4-related sclerosing disease or not is debatable and warrants further investigation.
Kumar, N., & Garg, N. (2013, July 9). Fibrosing mediastinitis causing ostial coronary artery compression in a young woman: Idiopathic or IgG4? Journal of the American College of Cardiology. https://doi.org/10.1016/j.jacc.2013.01.094