Abstract

Primary retroperitoneal neuroendocrine tumours (NETs) are extremely rare, and many a times, these are metastatic lesions with known or unknown primary location, most commonly arising from the stomach, duodenum, small intestine and rectum. NETs arising from the duodenum are more commonly seen in the first part of the duodenum followed by the second part. The incidence is increasing because of easy accessibility to endoscopies and cross-sectional imaging. In NETs, lymph node (LN) metastasis occurs commonly when the tumour size is more than 2 cm. In contrast, LN metastasis occurs even with subcentimetric lesions, especially the ampullary variant of NETs. A patient presented to us with mild abdominal pain and found to have retroduodenal mass. On evaluation found to be a metastatic LN deposit of NET with the primary arising from the first part and supra-ampullary part of duodenum.