Heterotopic ossification beneath the upper abdominal incision after radical gastrectomy: Two case reports

BACKGROUND: Heterotopic ossification (HO) is a rare clinical phenomenon that refers to bone formation in nonossifying tissues. CASE SUMMARY: This report presents two cases of HO beneath the upper abdominal median incision after radical gastrectomy. The first patient had postoperative pain below the incision area. There were no signs of anastomotic leakage, and the wound healed. Computed tomography (CT) findings 2 wk postoperatively were negative for HO, but the 6-wk CT showed HO beneath the incision. The patient refused reoperation, and after conservative therapy, the pain was gradually relieved after 2 wk. In the second case, postoperative recovery was uneventful, and HO was only detected on routine follow-up CT after 4 mo. An anti-adhesion membrane was applied beneath the peritoneum in both patients. Our findings suggest that HO beneath the abdominal incision might form at approximately 1 mo postoperatively. It may cause intractable pain; however, reoperation is usually not required. CONCLUSION: In our cases, we suspect that HO may be related to the use of foreign materials beneath the peritoneum, which needs to be further investigated.