IntroductionOsseous metaplasia in the gastrointestinal tract is a rare phenomenon.Case presentationWe present the case of a 62-year-old Hispanic man with two colonic polypoid lesions, one of which, upon resection and histopathological examination, was found to be a traditional serrated adenoma with a focus of stromal osseous metaplasia.ConclusionsOur patient’s case is the third report of stromal osseous metaplasia in a traditional serrated adenoma of the sigmoid colon.