Bone in the Colon: A Case of Osseous Metaplasia in a Juvenile Colonic Polyp

Osseous metaplasia is defined as the formation of bone at extra-skeletal sites. The occurrence of osseous metaplasia is rare in the gastrointestinal tract and even less common in the colon; a few reported cases in both adults and pediatrics have been reported. An osseous metaplasia is associated with both benign and malignant diseases, but the exact pathogenesis for this condition is unknown. A 14-year-old male presented with abdominal pain, alternating bowel habits, and urgency for the past three months, and he lost 5 kg unintentionally. He denies fever, blood in stool, extraintestinal manifestations, and nocturnal symptoms. His past medical and family history is unremarkable. His physical examination was normal, and he had a negative celiac screening, inflammatory markers, and fecal calprotectin. There was minimal improvement with peppermint oil, antispasmodics, and dietary modifications. Colonoscopy: a pedunculated polyp < 5 mm in the transverse colon; polypectomy done with epinephrine injection to elevate the stalk (1:100,000) and hot snare without complication. Histology revealed a juvenile polyp with osseous metaplasia. We report a rare incidental histological finding in a juvenile polyp that has been reported rarely worldwide with different gastrointestinal lesions. Although the underlying mechanism is unclear, further follow-up is needed to determine the prognosis and its significance.