Perforated Cecal Mucinous Adenocarcinoma with Heterotopic Ossification: A Case Report

Heterotopic ossification, also termed osseous metaplasia, is a known pathological condition of bone formation in extraskeletal sites. Its widespread occurrence in tumors is infrequent and the presentation in neoplasms of the gastrointestinal tract is very rare. Previous studies described different subtypes of benign and malign gastrointestinal tumors exhibiting areas of stromal osseous metaplasia. The relevance of its presence in the stroma of epithelial tumors, as well as the pathogenesis, remains still unknown. We report a case of mucinous carcinoma with osseous metaplasia. The tumor was located in the cecum and was composed of atypical epithelial glands, pools of extracellular mucin, calcifications, necrosis, and stromal osseous metaplasia. Metaplastic bone fragments histologically displayed a benign appearance. The tumor was staged as advanced and presented with perforation. Perforated colorectal carcinoma is frequently presented as an emergency case, and prompt surgical management is imperative.