Diagnosis and Management of Upper Gastrointestinal Neuroendocrine Tumors

Abstract

Upper gastrointestinal neuroendocrine tumors (NETs) are rare tumors which are increasingly recognised by practising endoscopists. After confirmation by endoscopic biopsies of these focal lesions, many questions may arise. As NETs are less frequently encountered compared to other malignancies or gastrointestinal pathology, many endoscopists may not fully understand the natural history, diagnosis and management of these tumors. In this review, we aim to update the practising endoscopist on the key clinical features and management of patients with upper gastrointestinal NET.

Keywords: Duodenal; Esophageal; Gastric; Neuroendocrine tumor.

Fig. 1.

(A) Classical type 1 gastric neuroendocrine tumors (g-NETs) or neoplasms with marked surrounding gastric mucosal atrophy, evident by loss of gastric folds. (B) Multiple type 1 g-NETs, larger 27 mm lesion (denoted by black arrows) and smaller 12 mm lesion (indicated by black arrowheads). Endoscopic ultrasound (EUS) showed large 27 mm g-NET was within submucosal layer but lymph nodes were pathologically enlarged, uT1N1. (C) EUS appearance of two small g-NETs (*); the larger measures 9 mm and smaller 6 mm in maximum dimensions and are seen to lie in the mucosa and submucosal compartments.

Fig. 2.

Type 2 gastric neuroendocrine tumor (g-NET) confined to mucosal layer on endoscopic ultrasound (denoted by orange line), with prominently hypertrophied gastric mucosal layer (indicated by yellow double arrows). This patient also had duodenal gastrinomas and Zollinger Ellison syndrome with multiple pancreatic NETs.

Fig. 3.

Example of a type 3 gastric neuroendocrine tumor in distal gastric body. (A) Endoscopically the lesion is quite large over 2.5 cm and is sessile with a broad, fixed base and a central depressed region. (B) At endoscopic ultrasound, the lesion can be seen to extend to touch the deep muscle layer (double arrow heads) and was predicted uT2 (N0) but after surgical resection the final pathological stage was pT2N1 (one single small node involved) with a Ki-67 of 30% (insert, C, ×200).

Fig. 4.

Endoscopic ultrasound showing a type 3 gastric neuroendocrine carcinoma (NEC) that is bulky on the posterior wall of the gastric antrum and is extending outside the gastric wall (double arrow heads) serosa (muscularis propria indicated). Surgery confirmed an aggressive NEC with a high Ki-67 of 60% and 4 positive lymph nodes.

Fig. 5.

(A) Small type 1 gastric neuroendocrine tumor approaching 1 cm in the mid-body greater curve. (B) Endoscopic mucosal resection performed using a cap assisted endoscopic mucosal resection device (Duette^® Multi-Band Mucosectomy Device; Cook Medical, Bloomington, IN, USA).

Fig. 6.

Sporadic duodenal neuroendocrine tumor in post pyloric position, (A) enhanced by virtual chromoendoscopy (Flexible spectral Imaging Colour Enhancement [FICE]; Fujifilm, Tokyo, Japan) and (B) on white light endoscopy.

Fig. 7.

Duodenal neuroendocrine tumor demonstrated by endoscopic ultrasound to show clear extension beyond the muscularis propria (yellow arrowhead) and therefore, not suitable for endoscopic mucosal resection.