Esophageal anisakiasis observed using magnifying endoscopy with narrow-band imaging

A 31-year-old man presented with a feeling of compression and intermittent pain in the epigastrium. He had eaten sliced raw fish (sashimi) for dinner at 10 pm on the previous night and developed epigastric symptoms 2 hours thereafter. Physical examination revealed no tenderness or rebound tenderness in the epigastrium; his vital signs and laboratory parameters were normal. He reported a history of similar epigastric symptoms when he had had gastric anisakiasis; therefore, esophagogastroduodenoscopy (EGD) was conducted. This revealed an Anisakis larva invading the mucosa of the distal esophagus, where a granulomatous reddish nodule approximately 2 mm in diameter was observed ([Fig. 1]). Magnifying endoscopy with narrow-band imaging (NBI) showed a rather flattened, smooth, and brownish nodule without vascular structure or surface pattern ([Fig. 2 a]). Closer view of the larva revealed a small whitish elongated spot (the ventricle, an organ distally adjacent to the esophagus of Anisakis larva), which is seen more clearly than with conventional white-light endoscopic observation ([Fig. 2 b]). After removing the parasite using biopsy forceps ([Video 1]), his symptoms reduced immediately. At the 1-month follow-up EGD, the nodule had disappeared.

Fig. 1 Esophagogastroduodenoscopy image showing an Anisakis larva invading the mucosa of the distal esophagus. At the invading site, a granulomatous reddish nodule approximately 2 mm in diameter is observed (arrowheads).

Fig. 2 Magnifying endoscopy with narrow-band imaging showing: a a nodule that is round, rather flattened, and smooth, with neither vascular structure nor surface pattern of the brownish lesion; b on closer view of the Anisakis larva, a small whitish elongated spot (arrows) that is seen more clearly than on conventional white-light endoscopic observation (the whitish spot corresponds to the ventricle that is an organ distally adjacent to the esophagus of Anisakis larva).

Video 1 Endoscopic observation of an Anisakis larva invading the esophageal mucosa using conventional white-light imaging and magnifying endoscopy with narrow-band imaging; thereafter, endoscopic removal of the larva is performed with biopsy forceps.

Anisakis infection most commonly affects the stomach and the small intestine [1]. Anisakiasis confined to the esophagus is very rare; only four cases have been reported thus far in the English literature [2] [3] [4] [5]. To our knowledge, this is the first case report that showed a nodular lesion of esophageal mucosa penetrated by an Anisakis larva, although it is well known that gastric anisakiasis may cause a tumor-like nodule or mass (also called “vanishing tumor”). When gastrointestinal symptoms that occur after a history of consumption of raw or undercooked fish or squid suggest Anisakis infection, not only the stomach and the duodenum but also the esophagus should be thoroughly examined endoscopically. A study of further cases is needed to clarify whether the nodular lesion, as seen in our case, is common in esophageal anisakiasis.

Endoscopy_UCTN_Code_CCL_1AB_2AG_3AD

Competing interests

The authors declare that they have no conflict of interest.

• References

• 1 Hochberg NS, Hamer DH. Anisakidosis: Perils of the deep. Clin Infect Dis 2010; 51: 806-812
• 2 Urita Y, Nishino M, Koyama H. et al. Esophageal anisakiasis accompanied by reflux esophagitis. Intern Med 1997; 36: 890-893
• 3 Muguruma N, Okamura S, Okahisa T. et al. Anisakis larva involving the esophageal mucosa. Gastrointest Endosc 1999; 49: 653-654
• 4 Uehara A, Okumura T. Esophageal anisakiasis mimicking gastroesophageal reflux disease. Am J Gastroenterol 2017; 112: 532
• 5 Ikegami K, Hirose Y, Yoneyama O. An unusual cause of severe epigastric pain. Gastroenterology 2018; 154: e7-e8

Publication History

Article published online:
26 June 2020