Literally, a congenital malformation of the intestinal lymphatic structures, and, in particular, of the small intestine and the mesentery, often associated with other malformations of lymphatic-lymph node structures in other body districts. From a pathological anatomy point of view, it features a dilatation of mucous and submucous lymphatic vessels of the intestinal wall and their subsequent functional insufficiency. It is often accompanied by lymphopenia – due to the leak of lymphocytes in the intestinal lumen – and with protein losing enteropaty. Its typical clinical manifestations may be observed also in other pathological processes involving intestinal and mesentery lymphatic-lymph node structures, and leading to their insufficiency (for example during TBC, Crohn’s disease, lymphomas with gastro-intestinal localization, enterites with various etiology, tumors with lymph node metastases, etc.).