We report the case of a 76-year-old woman with a flat elevated lesion (laterally spreading tumor; LST) in the transverse colon that had been identified 2 years before the current presentation. Pathologically, the lesion had been diagnosed asia serrated adenoma with severe dysplasia. The patient had refused endoscopic resection because she was afraid of the risk of colonic perforation; she did not come to follow-up until 2 years after the diagnosis, when she had advanced colon cancer in the transverse colon where the LST had been detected. Histopathological examination confirmed a poorly differentiated adenocarcinoma with no adenomatous component such as had been found in the LST lesion.
- Adenoma-carcinoma sequence
- De novo
- Laterally spreading tumor (LST)
- Serrated adenoma
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