Heterotopic mesenteric ossification (HMO) is a rare disease that results in intra-abdominal ossification of unknown origin. An 88-year-old man developed an intestinal obstruction 2 weeks after undergoing an operation for a ruptured abdominal aortic aneurysm, resulting in intestinal obstructions those did not improved concervatively. During relaparotomy performed 30 days after the first operation, hard adhesions of the small intestine and mesentery were found; these adhesions were difficult to separate without damaging the serosa of the small intestine. We removed 240 cm of the small intestine and performed a jejuno-ileo anastomosis. Microscopically, trabecular bone tissue had increased irregularly in the fat tissue of the nodules with fibrosis, which were partially lined with osteoblasts. Accordingly, we histopathologically diagnosed the patient as having HMO. The patient was treated with NSAIDs and cimetidine to prevent the recurrence of HMO. No signs of recurrence have occurred as of one year after the second operation.
Keywords: Aortic aneurysm; Heterotopic mesenteric ossification; Ileus; Obstruction; Small bowel.