Ileal anisakiasis: A report of two cases

ABSTRACT

Anisakiasis is a parasitic disease of the gastrointestinal tract caused by ingestion Of raw or undercooked fish containing the marine nematode larvae belong to the subfamily Anisakinae. The adult worms are intestinal parasites of marine mammals. Eggs are passed in the feces of these mammals and develop to the second stage larvae in the sea water. They are eaten by crustaceans in which the larvae develop to the third stage. When fish or squid eat the infected crustaceans the larvae migrate to the body cavity or the muscle. The infected fish or squid is eaten by marine mammals the larvae attach to the wall of the stomach and then undergo adult worm. In Korea, human anisakiasis is not rare. The clinical manifestations are variable and depend on the involving site of gastrointestinal tract. The frequent sites are stomach and small intestine, and large intestine is rarely involved. Recently we experienced two cases of ileal anisakiasis occurred in 54-year-old female and 46-year-old female patients. The symptoms were upper and lower abdominal pain, nausea, and vomiting. The resected ileums in case I and 2 measured 12.5 x 2.5 cm and 15.0 x 2.0 cm, respectively. The mucosa and submucosa were thickened. In case 1, submucosal penetration of a white thread-like parasite was seen. The ileum showed submucosal edema, and extensive infiltration of eosinophils, neutrophils, lymphocytes, histiocytes, and plasma cells from mucosa to mesentery with or without mucosal ulceration. The Anisakis larvae are found in the submucosa and propria muscle. They have thick multilayered smooth cuticle, many somatic muscle cells, triradiated esophagus with numerous tall columnar cells, renette cell, and Y-shaped lateral chords. Reproductive organ is absent. In Korea, the previously reported 14 cases and present 2 cases of the intestinal anisakiasis mainly involved ileum, but the cause was not mentioned.