Abstract
There has been increased detection of duodenal adenoma and early cancer. However, there are many equivocal aspects of their differential diagnosis in part due to their low frequencies. In addition, adenoma and early cancer are not easy to diagnose by biopsy, and endoscopic or pathological diagnosis is more challenging for lesions in the duodenum than in other parts of the digestive tract. There are also problems related to the indications for endoscopic therapy, technical difficulties, and high rates of complications. It is also important to understand non-neoplastic elevated lesions in differential diagnosis. Although Brunner's gland hyperplasia and ectopic gastric mucosa occur at high frequencies, differentiation is possible based on detailed observations, including findings under magnification. In addition, whitened villi are a characteristic of intestinal-type adenoma and intramucosal carcinoma and are an important finding. Further clinicopathological examination is necessary regarding the relationship between whitening and the mucin phenotype.
