2023 Volume 56 Issue 9 Pages 479-486
Echinococcosis is a parasitic disease that develops after infection with Echinococcus granulosus, but is rare in Japan. A 63-year-old Peruvian man who had immigrated to Japan 30 years ago presented to our hospital with complaints of abdominal pain and distension. CT and MRI revealed two hepatic cysts. The first cyst was a giant lesion that measured 30 cm in diameter, contained several internal septations, and was located in the lateral part of the liver. The second lesion measured 3 cm in diameter and was observed in segment 5 (S5) of the liver. Based on these findings, along with the patient’s residential history, hepatic echinococcosis was suspected, and lateral segmentectomy and S5 subsegmentectomy were performed. Both cysts had a thick fibrous capsule and a cuticular layer with a stratified eosinophilic structure. Echinococcus larvae were observed microscopically in fluid obtained from the cysts, and western blot analysis revealed E. granulosus-specific proteins. The patient was diagnosed with cystic echinococcosis, which is also referred to as hydatid disease. We suspect that the patient was infected with E. granulosus before moving to Japan. Most echinococcosis outbreaks in Japan are reported on the island of Hokkaido, and these cases are most often polycystic echinococcosis. Herein, we report a rare case of cystic echinococcosis in a Peruvian immigrant residing in Japan. An extensive review of the literature on echinococcosis in Japan is also provided.
