Gastric neuroendocrine neoplasms and precursor lesions: Case reports and literature review

Abstract

Rationale: Gastric neuroendocrine neoplasms (g-NENs) represent a distinctive group of gastric tumors, stratified into different prognostic categories according to different histological characteristics, put forth in the 2018 World Health Organization classification system. The clinical presentations, as well as pathological features, represent important data in establishing the type of the tumor, in estimating the tumor behavior, and in selecting the best therapeutic strategy. In our case series we presented different clinical scenarios that may be encountered in practice regarding gastric NENs. We performed a literature review and discussed diagnostic strategy, current classification system, precursor lesions, and therapeutic options in g-NENs.

Patient concerns: The first patient was a 41-year-old female with weight loss, persistent dyspeptic complaints and a history of pernicious anemia. In the second clinical case a 61-year-old man was admitted with heartburn, abdominal pain, diarrhea and mild iron deficiency anemia. The third patient was a 56-year-old male with a history of neoplasia, admitted for weight loss, dyspeptic complaints, and liver metastases.

Diagnosis: All the 3 patients underwent upper endoscopy with targeted biopsies. Histopathological and laboratory evaluation, together with imagistic evaluation (abdominal ultrasound, endoscopic ultrasound, and magnetic resonance imaging) allowed the distinction between 3 different types of gastric tumors: type 1 enterochromaffin-like-cell G1 NET, type 2 enterochromaffin-like-cell G2 NET, and type 3 G2 NET with liver metastases.

Interventions: Endoscopic polypectomy of the largest lesion was performed in patient with type 1 g-NET and autoimmune chronic atrophic gastritis, followed by regular endoscopic surveillance with biopsies. In type 2 g-NET associated with pancreatic gastrinoma, pancreaticoduodenectomy with total gastrectomy were performed. In type 3 g-NET, detected in metastatic stage, oncologic therapy was performed.

Outcomes: The patients follow-up was selected according to tumor behavior, from regular endoscopic surveillance to oncology follow-up. The prognosis was good in case 1, whilst poorer outcomes were associated with more aggressive tumors in case 2 and case 3.

Lessons: g-NENs are rare tumors with distinct clinical and histological features. Our case series emphasized the role of close collaboration between clinician and pathologist, as well as the importance of a detailed pathology report.

Figure 1

Endoscopic view of multiple polypoid lesions and corporeal atrophic gastritis.

Figure 2

Chromogranin immunostaining revealing a nodular proliferation of positive cells in the mucosa in the setting of extensive intestinal metaplasia and glandular atrophy (×2).

Figure 3

Endoscopic view of tumor with central ulceration in the gastric body (A) and a large duodenal ulcer (B).

Figure 4

Histological assessment of gastric and pancreatic lesions: (A) nodule of uniform neuroendocrine cells in the fundic type mucosa, with no intestinal metaplasia or glandular atrophy (HE, ×2); (B) immunohistochemical staining for Ki-67 of the gastric nodule (×2); (C) pancreatic tumor, well circumscribed, with a nested pattern (HE, ×2); (D) pancreatic tumor positive for gastrin (×2). HE = hematoxylin–eosin stain.

Figure 5

Endoscopic view of antral tumor (A) showing irregular pattern on NBI (B).

Figure 6

Histological assessment of gastric tumor and liver metastasis: (A) large nodules of uniform cells with neuroendocrine features in the antral mucosa (HE, ×4); (B) positive cells for chromogranin; (C) liver biopsy with large nodules of neuroendocrine cells, with pseudoglandular architecture (HE, ×4); (D) liver biopsy with positive cells for chromogranin (×2). HE = hematoxylin–eosin stain, NBI = narrow-band imaging.