In the left lower quadrant with the sigmoid mesocolon is a 43 x 44 mm rim enhancing collection containing gas locules surrounded by fat stranding and small lymph nodes. An adjacent short segment of sigmoid colon (approximately 55 mm) demonstrates slightly irregular circumferential mural thickening. There are a few small diverticula in the sigmoid colon.
No free peritoneal fluid or free gas.
The liver, spleen, pancreas, adrenals, kidneys, stomach and small bowel are unremarkable. Minor dependent changes in the lung bases. No suspicious osseous lesions.
Conclusion:
Localised perforation and poorly formed abscess due to perforation of a linear foreign body. Short segment mural thickening in adjacent sigmoid colon is likely secondary inflammatory change.