Heterotopic Mesenteric Ossification
Elizabeth A. Montgomery, MD
Key Facts
Terminology
Intraabdominal myositis ossificans
Metaplastic, probably reactive process variably associated with trauma
Clinical Issues
Adults; mean age: 50-60 years
Small bowel mesentery, omentum most common sites
Bowel obstruction
Microscopic Pathology
Exuberant myofibroblastic proliferation similar to nodular fasciitis
Fat necrosis
Abundant lace-like osteoid
Abundant bone
Plentiful mitotic activity
No abnormal mitoses
 This example of heterotopic mesenteric ossification arose in a patient who had a prior operation. The lesion was adherent to the liver, which shows bile plugs  from local obstruction. |
 Focus from the same lesion shows mature ossification in this area. The majority of patients with heterotopic mesenteric ossification have had prior surgery. |
TERMINOLOGY
Synonyms
Intraabdominal myositis ossificans
Definitions
Metaplastic, probably reactive process variably associated with trauma
Classically termed “myositis ossificans” when arising in soft tissues
CLINICAL ISSUES
Epidemiology
Incidence
Rare
Age
Adults; mean: 50-60 years
Site
Small bowel mesentery and omentum most common sites
Presentation
Bowel obstruction
Most patients have had prior abdominal surgery
Treatment
Surgical excision
