[Gastric neuroendocrine tumors]

Area of Science:

• Gastroenterology
• Oncology
• Pathology

Background:

• Gastric neuroendocrine tumors (gNETs) are rare neoplasms with a rising incidence.
• gNETs are classified into three distinct types, each with unique clinical characteristics, prognostic factors, and therapeutic approaches.

Purpose of the Study:

• To delineate the key features, clinical presentations, and prognoses of the three main types of gastric neuroendocrine tumors.
• To provide guidance on appropriate treatment strategies tailored to each gNET type.

Main Methods:

• Review of existing literature and clinical data on gastric neuroendocrine tumors.
• Classification of gNETs into Type I, Type II, and Type III based on etiology, hormonal association, and tumor characteristics.

Main Results:

• Type I gNETs (70-80%) are associated with chronic atrophic gastritis and hypergastrinemia, typically presenting as multiple, small, benign tumors.
• Type II gNETs (5-6%) are linked to MEN I and Zollinger-Ellison syndrome, also characterized by hypergastrinemia and small tumor size.
• Type III gNETs (10-15%) are not associated with hypergastrinemia, usually presenting as single, large, and malignant neoplasms.

Conclusions:

• Treatment strategies vary significantly by gNET type, with endoscopic approaches suitable for most Type I and II tumors.
• Type III gNETs generally require surgical resection and chemotherapy, though endoscopic surgery may be considered for small, well-differentiated cases.