Asymptomatic anisakiasis of the colon incidentally diagnosed and treated during colonoscopy by retroflexion in the ascending colon

Abstract

A 74-year-old man with diabetes underwent colonoscopy as routine screening for colon cancer. An Anisakis larva was found incidentally during colonoscopy using the retroflexion technique in the ascending colon, and was removed using a forceps. Asymptomatic colonic anisakiasis is very rare, and few reports have described diagnosis and treatment of anisakiasis during colonoscopy by the retroflexion technique in the ascending colon. We have reported this rare case along with a literature review.

Asymptomatic Colonic Anisakiasis: Is It So Rare?

“…Papers that were not written in English and papers that contained no description of the patient’s symptoms were excluded. Fourteen patients were identified; 6/15 patients (40.0%, including our patient) were asymptomatic [3]. Among the 9 symptomatic patients, the most common symptom was abdominal pain ( n = 7, 77.8%).…”

“…The stomach is the most common site of larval infection; the incidence of colonic anisakiasis is only 0.25% [2]. Without treatment, abdominal pain lasts from several weeks to 1 month, and more than half of colonic anisakiasis lesions are present on the right side [3]. Because of the nonspecific symptoms, such as abdominal pain, the differential diagnoses of symptomatic colonic anisakiasis are broad and include appendicitis, ileitis, diverticulitis, eosinophilic gastroenteritis, cholecystitis, colonic tumor, and inflammatory bowel disease [1].…”

Woman With Foreign Body on Her Tongue

“…1 Most Anisakis larvae commonly invade the stomach, and invasion of other parts of the digestive tract, especially the oral mucosa, is rare. 2,3…”

Excretory/secretory products of anisakid nematodes: biological and pathological roles

“…Diagnosis of anisakidosis initially relies on a detailed history of recent seafood consumption and may be confirmed by direct visualization and examination of the larvae. Removal of the worm by endoscopy/colonoscopy [ 96 ] or surgery [ 97 ] allows concurrent diagnosis and treatment of gastric/intestinal form of the disease, but non-invasive methods such as sonography and X-ray have also been proven as valuable diagnostic tools [ 98 – 100 ]. Haematological evaluations may show leukocytosis, e.g.…”