1. Department of Pathology and Bioscience, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036‑8562, Japan
2. Department of Gastroenterological Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036‑8562, Japan
3. Department of Radiology, Aomori National Hospital, Namioka, Aomori 038‑1338, Japan