OBJECTIVE Endoscopic biopsies of duodenal polyp/mass lesions are uncommon surgical pathology specimens. A surgical review with a report on three unusual duodenal polyp/mass lesions is presented. METHODS A computer-based data search of duodenal polyp/mass lesions was conducted at the Saskatoon Health Region using the Lab Information System from 1996 to 2009. The source codes used included DUOBX and DUO. Surgical material on the retrieved cases was reviewed. RESULTS The three index cases included duodenal polyp/mass lesions, which on primary analysis were diagnosed as 'poorly differentiated' carcinomas with some unusual features. The accurate diagnoses of metastatic renal cell carcinoma, metastatic phaeochromocytoma and metastatic malignant melanoma, respectively, were confirmed with retrospective analysis of previous clinical and pathological records. 130 duodenal polyp/mass related lesions were identified. 33% of these lesions were malignant and 67% were benign/normal. The majority of these biopsies originated in patients aged 60-79 years. Malignant lesions were more common in men (61%) than women (39%). 88% of the malignant cases were of carcinomatous origin. 16.3% of the carcinomas were reclassified as metastatic lesions arising from lung, breast, colon and pancreas. 41% of the benign cases had no significant pathological abnormalities. The remainder were predominantly adenomatous (14.9%) and inflammatory (13.8%) in origin. CONCLUSIONS Endoscopic biopsies of duodenal polyp/mass lesions remain an uncommon specimen (0.01% in the authors' surgical pathology practice). Nevertheless, accurate identification of the exact pathology, even in 'poorly differentiated' high-grade carcinomas is advocated, as metastatic lesions will require specific treatment plans in conjunction with treatment of their primary tumour.