Heterotopic mesenteric and abdominal wall ossification – Two case reports in one institution

INTRODUCTION Heterotopic ossification occurs when bone develops in tissues which usually don't undergo ossification. Heterotopic mesenteric ossification, also known as intra-abdominal myositis ossificans, is a rare and benign form of ossification, usually related with previous abdominal surgery or trauma. PRESENTATION OF CASES We report two cases of heterotopic ossification both after multiple abdominal surgeries, with intraoperative findings of mesenteric and abdominal wall ossification. Histopathology revealed metaplastic bone deposition, without evidence of atypia or malignancy. DISCUSSION This rare entity shares clinical and pathological characteristics of myositis ossificans. It is important to consider the differential diagnosis with sarcomas. In the cases described, the patients were proposed for elective surgery and this pathology was as an incidental finding. CONCLUSION The simultaneous presence of mesenteric and abdominal wall ossification in both patients makes these cases even rarer.