Clinical Challenges and Images in GI

Abstract

Question: A 63-year-old man with no significant medical history presented with obscure abdominal discomfort. He underwent computed tomography (Figure A), which revealed a mass in the pelvic cavity. The mass was a smooth-surfaced, egg-shaped lesion with a central low-density area. Magnetic resonance imaging was performed to confirm the finding (Figure B). T1-weighted images showed a low-intensity mass with a central high-intensity area. The mobile, hard mass was palpable by digital examination; however, colonoscopy revealed normal rectal mucosa and no submucosal tumor. Further physical examination and laboratory investigations showed normal findings. What is the diagnosis?View Large Image Figure ViewerDownload Hi-res image Download (PPT) Look on page 730 for the answer and see the Gastroenterology website (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. Pelvic CT scan showed a 45- × 40-mm mass and MRI demonstrated a low-intensity mass. In both investigations, the mass was found to show the same degree of intensity as the surrounding muscle tissue. A high-intensity area was observed in the center of the mass, identical to that seen in fatty tissues. The patient underwent laparoscopic surgery. We found a hard, white, egg-shaped peritoneal loose body that was completely free in the pelvic cavity (Figure C). The mass was laparoscopically removed using an endopouch. It was composed of many layers of laminated, fibrous tissues surrounding a central necrotic fatty lesion (Figure D). This mass was a “peritoneal loose body” as defined by the intraperitoneal separate body, which was mainly made from protein and calcium phosphate.View Large Image Figure ViewerDownload Hi-res image Download (PPT) The general conception of peritoneal loose bodies is that they arise owing to torsion and separation of the appendices epiploicae, which are visceral peritoneal pouches filled with fat that exist along the antimesenteric tenia of the colon. It is important to differentiate peritoneal loose bodies from other lesions such as gastrointestinal stromal tumors (GIST), fibromas, desmoid tumors, teratomas, and urinary, gallbladder, and appendix stones. GIST is especially hard to distinguish from peritoneal loose bodies; however, the former exhibits a contrast-enhancing effect unlike peritoneal loose bodies, which require additional prone-positioned computed tomography examinations to monitor their mobility. A huge peritoneal loose body (∼10 cm) has been reported previously.1Mohri T. Kato T. Suzuki H. A giant peritoneal loose body: report of a case.Am Surg. 2007; 73: 895-896PubMed Google Scholar Such loose bodies rarely cause any symptoms if they are small (0.5–2.5 cm in diameter); however, “giant” peritoneal loose bodies (>5 cm in diameter) present with various symptoms.2Ghosh P. Strong C. Naugler W. et al.Peritoneal mice implicated in intestinal obstruction: report of a case and review of the literature.J Clin Gastroenterol. 2006; 40: 427-430Crossref PubMed Scopus (29) Google Scholar, 3Bhandarwar A.H. Desai V.V. Gajbhiye R.N. et al.Acute retention of urine due to a loose peritoneal body.Br J Urol. 1996; 78: 951-952Crossref PubMed Google Scholar If CT or MRI images reveal a huge peritoneal loose body, laparoscopic surgery is indicated, unlike cases that show small loose bodies.4Nomura H. Hata F. Yasoshima T. et al.Giant peritoneal loose body in the pelvic cavity: report of a case.Surg Today. 2003; 33: 791-793Crossref PubMed Scopus (25) Google Scholar In this case, abdominal discomfort disappeared spontaneously before operation. Therefore, we believe only symptomatic or cases that have significant findings should be treated surgically.