Giant retroperitoneal lymph node-an uncommon presentation of duodenal neuroendocrine tumour

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.

Keywords: gastrointestinal surgery; stomach and duodenum; surgical oncology.

Figure 1

(A) Axial image depicting well-defined hypodense lesion retroduodenal lymph nodal mass. (B) Endoscopic view of duodenum showing submucosal lesion with central umbilication. (C) Resected specimen of the distal stomach and proximal duodenum along with lymph nodal mass. (D) Cut section resected specimen showing submucosal nodule in proximal duodenum (solid white arrow).

Figure 2

(A) Metastatic tumour deposits were seen in the locoregional lymph nodes dissected from the attached mesentery (200×, H&E). (B and C) The larger mesenteric mass (sent separately) showed large central areas of haemorrhage. The periphery of the mass showed preserved nodal architecture, which was largely replaced by a morphologically similar tumour (100× and 400×, H&E). (D) Inset shows the Ki67 index, which is 1%.