Abstract
Background Chronic gastric anisakiasis is a rare, usually asymptomatic, and difficult to diagnose infection incidentally discovered during endoscopy, resembling a subepithelial tumor (SET). Because its endoscopic ultrasonography (EUS) findings are not established, it is occasionally misdiagnosed as gastrointestinal mesenchymal tumors and removed by endoscopic or surgical resection. We aimed to assess the characteristic EUS findings of chronic gastric anisakiasis and the clinical course during follow-up. Methods The database of all patients who underwent EUS at Pusan National University Hospital (Busan, Korea) between January 2011 and December 2016 was retrospectively analyzed. A total of 28 SET cases with EUS features suggesting chronic gastric anisakiasis were included in the study. The EUS, histopathologic, and follow-up endoscopic features were analyzed. Results On EUS, the lesions were mainly located in the submucosal and/or propria muscle layers. Twenty-seven lesions (27/28, 96%) showed hypoechoic echogenicity, and 22 lesions (22/28, 79%) were heterogeneous. Hyperechoic tubular structures suggesting denaturalized Anisakidae larvae were seen in 22 lesions (22/28, 79%). Endoscopic biopsies revealed significant eosinophil infiltration (≥30 per high-power field) in 12 lesions (12/21, 57%). During the median follow-up period of 9 months (range, 1–55 months), SETs decreased or subsided in 26 lesions (26/28, 93%) with no change in the size of the two lesions (2/28, 7%). Conclusions Chronic gastric anisakiasis, although rare, should be included in the differential diagnoses for gastric SETs, especially in regions where raw fish is widely consumed. EUS findings suggesting chronic gastric anisakiasis are heterogeneously hypoechoic lesions with hyperechoic tubular structures, mainly in the submucosal and/or muscularis propria layers. Because chronic gastric anisakiasis decreases or subsides in most cases, follow-up endoscopy 6–12 months later is recommended.
Highlights
Anisakiasis is a parasitic disease caused by an accidental ingestion of the nematode larva of the Anisakidae family in uncooked saltwater fish
Based on our previous cases of histologically confirmed chronic gastric anisakiasis (Figure 1), we identified 38 subepithelial tumor (SET) cases with endoscopic ultrasonography (EUS) features suggesting chronic gastric anisakiasis
As shown by the EUS, the lesions were mainly located in the third and/or fourth layers and ranged from 3 mm to 25 mm in size (Table 2)
Summary
Anisakiasis is a parasitic disease caused by an accidental ingestion of the nematode larva of the Anisakidae family in uncooked saltwater fish. This disease is caused by eating infected raw, pickled, or salted fishes such as herring, mackerel, squid, salmon, bonito, tuna, and cuttlefish. A total of 28 SET cases with EUS features suggesting chronic gastric anisakiasis were included in the study. Rare, should be included in the differential diagnoses for gastric SETs, especially in regions where raw fish is widely consumed. EUS findings suggesting chronic gastric anisakiasis are heterogeneously hypoechoic lesions with hyperechoic tubular structures, mainly in the submucosal and/or muscularis propria layers. Because chronic gastric anisakiasis decreases or subsides in most cases, follow-up endoscopy 6–12 months later is recommended
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
