Osseous metaplasia in an adenocarcinoma of the cecum: A rare case report.

INTRODUCTION: Osseous metaplasia (OM) is a rare condition characterized by formation of bone outside of the skeletal system. It is a rare phenomenon in the gastrointestinal tract. OM in colon cancer was first reported by Duckes in 1939. The aim of this case report is to highlight the possible occurrence of OM in colorectal carcinoma. CASE PRESENTATION: A 46-year-old female patient known to have type two diabetes mellitus presented to the emergency department with a complaint of abdominal pain lasting 15 days. Her abdomen-pelvic ultrasound revealed a right lower quadrant focal collection. Right hemicolectomy with abscess drainage was performed with an assessment of appendiceal abscess. Histologic examination showed well-differentiated adenocarcinoma with osseous metaplasia. DISCUSSION: OM has been observed in the gastrointestinal tract, linked to benign gastric and colonic polyps, adenomas, and various carcinomas, especially in the rectum. It typically affects individuals aged 32 to 90 and is frequently associated with well to moderately differentiated adenocarcinomas. The mechanisms behind metaplastic bone formation in these lesions are unclear, though overexpression of osteogenic factors like bone morphogenetic proteins (BMPs) is suspected. OM can mimic mesenchymal tumors, necessitating careful histopathological examination to distinguish it from metastasis. CONCLUSION: To our knowledge, this is the first report of OM in colon adenocarcinoma in an Ethiopian patient. It should be differentiated from osteosarcoma and metastasis of carcinoma to the bone, as the latter two have worse prognoses. Further studies are necessary to determine its etiology, pathogenesis, and prognostic significance of OM in colon adenocarcinoma.