Juvenile Rectal Polyp Exhibiting Osseous Metaplasia: A Case Report.

A 10-year-old boy presented with painless rectal bleeding. No fever or weight loss was reported. He had no history of constipation. Ileocolonoscopy revealed a single 2 cm pedunculated polyp in the distal rectum, which was removed endoscopically. Histological examination demonstrated polypoid tissue with focal ulceration characterized by an inflamed lamina propria containing dilated, branched, and hyperplastic crypts. Higher-power microscopy revealed mature bony trabeculae within the lamina propria. No dysplasia was observed. Osseous metaplasia is generally regarded as clinically and prognostically insignificant and is typically an incidentalhistological finding. We report an extremely rare case of heterotopic bone formation in a juvenile rectal polyp and review recent literature on this phenomenon.