Duodenal adenomatous polyps are usually classified according to the mucin phenotype into intestinal (89.1%) and gastric type (10.9%). The intestinal-type polyps are morphologically divided into tubular and tubulo-villous adenomas, whereas the gastric-type into pyloric gland adenomas and foveolar adenomas. The duodenal adenomas are also clinically categorised into sporadic duodenal adenomas and adenomas associated with genetic syndromes for instance familial adenomatous polyposis (FAP), or MUTYH associated adenomatous polyposis (MAP). Sporadic duodenal adenomas are less common than FAP related adenomas and are usually recognized in elderly men in their 6 to 8 decade of life. The large non-ampullary solitary duodenal adenomas ≥ 20 mm in diameter with high grade dysplasia show a significantly high risk of progression to adenocarcinoma and therefore, must be treated immediately. Our case, is a middle-aged female who presented with symptoms and had an exophytic duodenal mass of about 60mm in diameter, microscopically showing tubulo-villous intestinal pattern with high grade dysplasia and no breach in muscularis mucosae, thereby making it a case with distinct presentation and characteristics.