2013 年 29 巻 2 号 p. 443-447
A 43 year-old woman, gravida 3, para 3, presented with a right inguinal mass. It was growing slowly and associated with cyclic pain during the menstrual cycle. She had no other symptoms such as dysmenorrhea or pelvic pain. On examination, the right inguinal mass measured 50 mm. It was relatively fixed and nontender. Laboratory values were normal, including CA19-9, CA125, and CEA. She had a history of a laparoscopic cholecystectomy at 33 years of age. Magnetic resonance imaging (MRI) showed a multiple cystic lesion with in inguinal fatty tissue or in the inguinal canal; it measured 52 mm at its larger axis. We diagnosed it as inguinal endometriosis and resected the tumor. A 30 × 50 mm cystic tumor was removed; it contained a metallic clip. The pathological examination was reported as endometriosis in a canal of Nuck hydrocele. The origin of the metallic clip was thought to be an instrument, which was used in laparoscopic cholecystectomy, because she had no history of trauma or surgery in the inguinal area. The metallic clip migrated from the cystic duct or the artery of gallbladder, transited the inguinal canal, then fell into the canal of Nuck hydrocele. This is a very rare case of endometriosis in a canal of Nuck hydrocele, which contained a metallic clip.