-Case Reports-

A Case of a Fixed Giant Peritoneal Loose Body outside the Peritoneum and near the Rectovesical Excavation

Kotaro Nanno, Seiichi Shinji, Takeshi Yamada, Akihisa Matsuda, Ryo Ohta, Hiromichi Sonoda, Takuma Iwai, Kohki Takeda, Kazuhide Yonaga, Koji Ueda, Sho Kuriyama, Toshimitsu Miyasaka, Hiromasa Komori, Yoshinobu Shioda and Hiroshi Yoshida

Departments of Gastrointestinal and Hepato-Biliary-Pancreatic Surgery, Nippon Medical School, Tokyo, Japan

A peritoneal loose body (PLB) is tissue completely separated from other intraperitoneal organs. It is rare and usually found incidentally during laparotomy, examination, or autopsy. PLBs are usually located free in the peritoneal cavity and not in the extraperitoneal space. They are thought to originate when epiploic appendices are released into the abdominal cavity after ischemic necrosis. We report a case of a giant PLB outside the peritoneal cavity, adjacent to the rectovesical excavation, that was identified preoperatively inan asymptomatic 83-year-old man undergoing evaluation for cholecystolithiasis. Computed tomography revealed a mass with well-defined margins in the rectovesical excavation. The mass (diameter, 60 mm) consisted of a calcified core and peripheral soft tissue and did not appear to invade adjacent organs. Although there were no symptoms or tumor growth over time, we scheduled a laparoscopic extraction for definitive diagnosis. On laparoscopic exploration, a white ovoid mass was found in the rectovesical excavation; there was no invasion of adjacent organs. We diagnosed a giant PLB. Postoperative recovery was uneventful. Most PLBs are asymptomatic and do not require surgery, except when symptoms are present, when the PLB is large, or when malignancy is suspected. PLB is rarely extraperitoneal and is usually freely mobile; however, in our patient, it was fixed and outside the abdominal cavity, near the rectovesical fossa. Although it could not be diagnosed preoperatively as being extraperitoneal, imaging findings were typical of PLB; thus, it was possible to remove the mass laparoscopically without bowel resection.

J Nippon Med Sch 2023; 90: 276-281

Keywords
extraperitoneal, peritoneal loose body, giant, fixed, laparoscopic surgery

Correspondence to
Seiichi Shinji, MD, PhD, Departments of Gastrointestinal and Hepato-Biliary-Pancreatic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan
s-shinji@nms.ac.jp

Received, September 19, 2021
Accepted, November 22, 2021