Easy Detection and Fast Removal of Gastric Anisakis during Narrow-Band Imaging Endoscopy with L-Menthol Administration

Anisakiasis is a parasitic disease caused by the ingestion of raw or uncooked seafood infected with third-stage larvae of the anisakid nematodes. A 45-year-old Japanese man presented with epigastric pain and itchy skin with rash on his arm, chest, and back after eating vinegar-marinated raw mackerel sushi. He underwent an emergent endoscopic examination using narrow-band imaging (NBI) that revealed two anisakid larvae. NBI showed the larvae more clearly than white light imaging on the cardiac region of the stomach. We sprayed L-menthol on the larvae for stopping their movement and then easily removed them using biopsy forceps. The macroscopic examination and genotype analysis of the specimens revealed the two larvae as belonging to A. simplex sensu stricto. Our case demonstrates the usefulness of endoscopic examination with NBI and of the L-menthol spray in visualizing and immobilizing the larvae for removal.