Magnifying endoscopic findings of early-stage poorly differentiated colorectal adenocarcinoma: a case report

BACKGROUND: Colorectal poorly differentiated adenocarcinoma is rarely founded, especially in early-stage. Endoscopic features of early poorly differentiated colorectal cancer in magnifying endoscopy and chromoendoscopy haven’t been clarified. CASE PRESENTATION: A 49-year-old man was referred to our hospital for endoscopic treatment of a lateral spread tumor located in the rectum. We performed pre-resection endoscopic examination for the patient. In magnifying endoscopy with crystal violet staining, the lesion showed irregular microvessels and turned out to be poorly stained with predominantly non-structural pit pattern and a few roundish pits scattered on the surface. The histology revealed a poorly differentiated adenocarcinoma of the rectum invading the deep submucosal layer with negative lymphovascular invasion. CONCLUSIONS: In this case report, we presented a case of poorly differentiated colorectal adenocarcinoma detected at an early stage, showing interesting endoscopic findings in magnifying endoscopy with crystal violet staining.