Inflammatory Rectal Polyp with Osseous Metaplasia: Is It a Distinctive Disease Entity?

Osseous metaplasia is a heterotopic bone formation and it is encountered rarely in the gastrointestinal tract, especially in benign lesions. Although its pathophysiology is not known clearly, there are several theories suggested. In this case report, we presented a case of bone formation in a rectal inflammatory polyp presenting with rectal bleeding in a 7-year-old girl. Therewithal, we reviewed the literature and summarized the subject of osseous metaplasia in colon polyps. We detected some similarities in the cases presented that suggest it might be a distinctive disease entity. Osseous metaplasia in colorectal polyps is extremely rare. To our knowledge, this is the eleventh reported case of osseous metaplasia in a rectal inflammatory polyp. Although osseous metaplasia in colon polyps has not a significant effect on both clinic and the prognosis, it can be confusing when encountered in microscopic examination. [ABSTRACT FROM AUTHOR]