Giant loose bodies (peritoneal mice) are very rare and only a few cases have been reported in literature [[1–10]]. The exact pathogenesis of loose bodies has not been fully demonstrated, however the current hypothesis as mention previously by many authors [[6, 8–10]] suggests that it is a sequential process which starts with torsion of an epiploica, followed by ischemia, saponification and calcification. The pedicle atrophies and finally it detaches from the colon surface to become a loose body.
We believe that once an appendix epiploica gets saponified and calcified the exudative serum fluid (rich in protein) accumulates around it and, because of increased temperature in the peritoneal cavity, it gives the appearance of a boiled egg. With time, the size of the peritoneal body increases because of a gradual deposition of body serum at the periphery. Sometimes the free peritoneal body attaches to the omentum and receives a blood supply from it (a parasitized peritoneal body), as in our case.
Our histological findings suggest that saponified and calcified appendices epiploicae form the yellow central part and gradual deposition of peritoneal serum around it form the outer white layer, hence giving the appearance of a boiled hen's egg.
Pre-operative diagnosis of these lesions is difficult, because most of the time these lesions are asymptomatic and found during routine exploration of the abdomen for some other pathology.
The most common form of presentation in symptomatic patients is causing intestinal obstruction, as in this case. If a patient presents with features of intestinal obstruction and X-ray films shows a calcified lesion in the abdomen, which moves with a change in position of the patient, there should be a high index of suspicion for diagnosis of a giant loose peritoneal body. Additional tests which can be done to diagnose peritoneal mice are CT and MRI scans, which can be useful for differentiating these from other lesions. However, it is very difficult to differentiate between these loose bodies and other abdominal benign lesions with calcification, like granuloma or tuberculosis.
In our case, because the patient presented with acute intestinal obstruction and an X-ray of his abdomen only showed multiple air-fluid levels and no calcified lesions, our patient was directly taken up for an urgent laparotomy without waiting for CT or MRI scans.