Rectal Polyp with Osseous Metaplasia: A Case Report and Review of the Literature

Nitin Rangrao Gaikwad; Sudhir Jagdishprasad Gupta; Kirti Jaiswal

doi:10.5812/acr.84950

Rectal Polyp with Osseous Metaplasia: A Case Report and Review of the Literature

Nitin Rangrao Gaikwad ^{1
, *} , Sudhir Jagdishprasad Gupta ¹ and Kirti Jaiswal ¹

Authors Information

¹ Department of Gastroenterology, Government Medical College and Super Specialty Hospital, Nagpur, Maharashtra, India

Article information

Annals of Colorectal Research: December 2018, 6 (4); e84950
Published Online: November 27, 2018
Article Type: Case Report
Received: October 4, 2018
Accepted: October 13, 2018
DOI: 10.5812/acr.84950

To Cite: Gaikwad N R, Gupta S J, Jaiswal K. Rectal Polyp with Osseous Metaplasia: A Case Report and Review of the Literature, Ann Colorectal Res. 2018 ; 6(4):e84950. doi: 10.5812/acr.84950.

Abstract

Copyright © 2018, Annals of Colorectal Research. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited.

1. Introduction

2. Case Presentation

A four-year-old boy was presented to the department of gastroenterology with history of intermittent bleeding per rectum since last one year. He never required blood transfusion. There was no history of abdominal pain, fever, vomiting, and abdominal distension, or any mass coming out of the anus. Physical examination was unremarkable. Complete blood count, liver, and kidney function tests were within normal limits. Coagulation profile, including PT/INR, was in the normal range. The patient underwent colonoscopy preparation by ingesting polyethylene glycol along with water. Colonoscopy was done under conscious sedation. It revealed 1.5 cm × 1 cm polyp with a short stalk at 5 cm from the anal verge (Figure 1). Polypectomy was done and the entire rectal polyp was sent for histological examination. Sections from the polyp showed partly ulcerated and partly covered columnar epithelium. Fibrocollagenous core with dense inflammatory infiltrate, comprised of lymphocytes, plasma cells, and at times pigment laden macrophages with osseous metaplasia, was seen. The impression of hamartomatous rectal polyp with osseous metaplasia was indicated (Figure 2A and 2B). The post-polypectomy patient had a normal uncomplicated course at the ward.

Figure 1. Rectal polyp on colonoscopy

Figure 2. A, H&E staining showing hamartomatous polyp; B, Osseous metaplasia in polyp

3. Discussion

The formation of bone, apart from the bony skeleton, can occur pathologically in many situations. It may sometimes be of clinical significance as in generalized myositis ossificans, however, at times it may not have any effect on the prognosis of the patient in many benign conditions.

Osseous metaplasia, which occurs in colonic polyp, is extremely rare in the literature (1).

Pathogenesis of osseous metaplasia still remains unknown. Formation of bone is a rare occurrence in the gastrointestinal tract. This type of osseous metaplasia is mostly associated with mucin-producing tumours of the appendix and large intestine (2).

Stromal ossification in the gastrointestinal malignancies results from tumor production of bone morphogenetic protein (BMP) (3). Although the exact etiology for heterotrophic bone formation in gastrointestinal cancers is not known, the postulated reasons may be extracellular mucin deposition, hypervascularity, active inflammation and necrosis, and pre-existing calcification.

The literature also suggests the possibility of osseous metaplasia resulting because of the ability of fibroblasts to convert to osteoblasts (4).

Juvenile polyps are hamartomatous polyps. In a previously published review of the literature by Odum et al. seventeen cases of osseous metaplasia in colonic polyps have already been reported. Odum et al. also published a case of osseous metaplasia in an inflammatory polyp of the rectum (5).

Cavazza et al. described osseous metaplasia in a tubulovillous adenoma (6).

Occurrence of osseous metaplasia mostly occurs in adenomatous polyps. Ten cases of osseous metaplasia have been reported in benign colonic polyps, out of which four were reported in inflammatory polyps (7). An osseous metaplasia is often an incidental finding, which barely has clinical and prognostic significance.

In the present case of juvenile polyp, the pathogenesis could be the result of a metaplastic conversion of the fibroblasts to osteoblasts.

3.1. Conclusion

Osseous metaplasia is a prominent and unique histological finding. This was a mere incidental histological finding in the current case of hamartomatous polyp and does not have any clinical or prognostic significance. The pathogenesis of osseous metaplasia in gastrointestinal tract polyps and tumors is unclear, yet rarity of this occurrence makes it a notifiable condition.

Footnotes

References

1. Hjelkrem M, Fair K, Pabby A. Osseous metaplasia in a colon polyp. Pract Gastroenterol. 2012;36(11):58-62.
2. Alper M, Akyurek N, Patiroglu TE, Yuksel O, Belenli O. Heterotopic bone formation in two cases of colon carcinoma. Scand J Gastroenterol. 2000;35(5):556-8. doi: 10.1080/003655200750023859. [PubMed: 10868462].
3. Haque S, Eisen RN, West AB. Heterotopic bone formation in the gastrointestinal tract. Arch Pathol Lab Med. 1996;120(7):666-70. [PubMed: 8757473].
4. Marks MM, Atkinson KG. Heterotopic bone in a juvenile rectal polyp: Case report. Dis Colon Rectum. 1964;7:345-7. doi: 10.1007/BF02616838. [PubMed: 14176152].
5. Odum BR, Bechtold ML, Diaz-Arias A. Osseous metaplasia in an inflammatory polyp of the rectum: A case report and review of the literature. Gastroenterology Res. 2012;5(2):74-8. doi: 10.4021/gr417w. [PubMed: 27785185]. [PubMed Central: PMC5051171].
6. Cavazza A, Sassatelli R, De Marco L. [Bone metaplasia in adenomatous intestinal polyp. Report of a case and review of the literature]. Pathologica. 1996;88(6):511-3. Italian. [PubMed: 9206779].
7. Castelli MF, Roberts J. Ossification in a benign rectal polyp. Am J Gastroenterol. 1992;87(4):543-4. [PubMed: 1553950].

Annals of Colorectal Research

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Rectal Polyp with Osseous Metaplasia: A Case Report and Review of the Literature

Article information

Abstract

1. Introduction

2. Case Presentation

3. Discussion

Footnotes

References

Readers' Comments

Annals of Colorectal Research

Published by: Kowsar

Rectal Polyp with Osseous Metaplasia: A Case Report and Review of the Literature

Article information

Abstract

1. Introduction

2. Case Presentation

3. Discussion

Footnotes

References

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