A case of giant peritoneal loose bodies mimicking calcified leiomyoma originating from the rectum.

Two giant peritoneal loose bodies were found in the pelvis in a 79-year-old man. These bodies were demonstrated by computed tomography and magnetic resonance imaging to be well circumscribed masses and to have marked calcification in their central portion. Preoperatively, these bodies had been diagnosed as a calcified leiomyoma originating from the rectum; however, surgery revealed these lesions to be detached appendices epiploica. Histological examination showed that these peritoneal loose bodies consisted of thin layers of eosinophilic substance and had no cellular component. Small peritoneal loose bodies are occasionally found during laparotomy, but such large ones measuring 6 cm are very rare. In our case, accurate diagnosis could not be obtained preoperatively, because these loose bodies mimicked calcified leiomyoma of the rectum.