Heterotopic Mesenteric Ossification (`Intraabdominal Myositis Ossificans')

Abstract

Intraabdominal heterotopic ossification is a very uncommon disorder. We report five new cases, review the previous literature, and discuss the clinical and pathologic features of these lesions. The clinical features of the current cases and of those previously reported are remarkably similar. All patients were middle-aged to elderly men (range, 43-80 years; mean, 61 years) who had small bowel obstruction associated with heterotopic bone formation in the small bowel mesentery, often after one or more abdominal operations. In one case, an initial diagnosis of extraosseous osteosarcoma was considered. This unusual reactive process shares many of the clinical and pathologic features of myositis ossificans, as classically described in somatic soft tissues. We propose to designate this condition heterotopic mesenteric ossification.

Secondary Tumors and Tumorlike Lesions of the Peritoneal Cavity: Imaging Features with Pathologic Correlation

“…Osseous metaplasia has been described more frequently in men and chrondroid metaplasia more frequently in women (75). Its pathogenesis is not entirely clear, and it has been postulated that it represents metaplasia of the submesothelial mesenchyme, although implantation of osteoblasts or periosteum during trauma or procedures cannot be entirely excluded (76,77). Because the lesion has a core of reactive myofibroblasts with hemorrhage and fat necrosis, osteoblastic activity, and at least focal "lace-…”

Heterotopic mesenteric ossification: a case report (2004:10b)

“…Unassociated with neoplasms however, ectopic bone formation in the mesentery is an extremely rare entity of unknown cause. The designation "heterotopic mesenteric ossification" was first introduced by Wilson et al in 1999 as "an exuberant reaction to trauma in a predisposed individual" [1]. It is thought to be a metaplastic process in which local pluripotent mesenchymal cells differentiate to form osteoblasts, due to certain chemical or physical stimuli [4,5].…”

“…spinal cord injury). In the mesentery, however, heterotopic bone formation is extremely rare and of unknown aetiology [1,2]. It may lead to serious complications, such as small bowel obstruction and even death.…”

Cartilaginous Differentiation in Peritoneal Tissues: A Report of Two Cases and a Review of the Literature

“…In the human peritoneum, at least seven welldocumented cases of mesenteric heterotopic ossification (or osseous metaplasia) have been reported (15)(16)(17). The fact that 6 of those 7 cases were associated with a history of abdominal surgery underscores the ability of the peritoneal tissues to differentiate into heterologous tissues in response to injury.…”