Mesenteric tumour deposits arising from small‐intestine neuroendocrine tumours are frequently associated with fibrosis and IgG4‐expressing plasma cells

Abstract

IgG4 expression is frequent in mesenteric tumour deposits from small-intestine neuroendocrine tumours. Undersampling of tumour on biopsies of mesenteric tumour deposits could potentially cause diagnostic confusion with IgG4-related sclerosing mesenteritis.

68Ga-DOTATATE PET/CT Distinguishes Neuroendocrine Tumor Mesenteric Lymph Node Metastasis From an Extensive IgG4-Positive Fibrosis Surrounding It

“…5,6 IgG4 expression is commonly seen in mesenteric tumor deposits from small intestine neuroendocrine tumors leading to a dense fibrotic response, which can simulate IgG4-related sclerosing mesenteritis in medical images, hereby impeding a correct diagnosis. 7 IgG4-releated disease is an inflammatory process characterized by a dense lymphoplasmacytic infiltrate containing IgG4-positive plasma cells and storiform fibrosis. In addition, elevated serum IgG4 levels can be seen, but this is not always the case and not necessary to make the diagnosis.…”

“…However, MF and CHD usually do not coincide, suggesting that different pathophysiological mechanisms form the basis of these fibrotic reactions 5,6 . IgG4 expression is commonly seen in mesenteric tumor deposits from small intestine neuroendocrine tumors leading to a dense fibrotic response, which can simulate IgG4-related sclerosing mesenteritis in medical images, hereby impeding a correct diagnosis 7 . IgG4-releated disease is an inflammatory process characterized by a dense lymphoplasmacytic infiltrate containing IgG4-positive plasma cells and storiform fibrosis.…”