Heterotopic bone formation in abdominal scars.

Twelve patients with heterotopic ossification in abdominal scars have been studied. Two patients were elderly females. Operative excision was required in seven: two for local symptoms, two for suspected local malignant recurrences and three for further intra-abdominal procedures. The other five instances were diagnosed roentgenologically. The mechanisms of formation of such lesions are not clear, but both the implantation and metaplasia theories may be correct.