OBJECTIVEThe aim of this study was to investigate the clinicopathological features of different histological types of primary gastric neuroendocrine neoplasms (including the esophagogastric junction), and to analyze the characteristics and difficulties in diagnosis of all the subtypes of this disease.

METHODS75 cases of primary gastric neuroendocrine neoplasms (including the esophagogastric junction) were included in this study. The expressions of several markers including somatostatin, synaptophysin, chromogranin A, CD56, S-100, neuron-specific enolase and CD57 were assayed in all the specimens by immunohistochemical staining, and their significance in the diagnosis and prognosis of gastric neuroendocrine neoplasms were assessed. In addition, the relationship between various clinical parameters such as tumor location, histological types, depth of invasion and metastasis was also analyzed.

RESULTSThe incidence of gastric neuroendocrine neoplasms accounted for 1.5% of gastric cancer in the same period, and the proportion of each subtype was 53.3% (40/75) in G3, 29.3% (22/75) in MANEC, 16.0% in G1(12/75), and 1.3% (1/75) in G2, respectively. 41.7% (5/12) of the G1 showed multifocal lesions, accompanyied with neuroendocrine cell hyperplasia in the gastric mucosa. 54.67% (41/75) of the NEN located in the esophagogastric junction. The lymph node metastasis of MANEC is unique. The coincidence rate in diagnosis of preoperative biopsies and postoperative specimen was 75.0% (9/12) in G1, 72.7% (16/22) in MANEC, and 25.0% (10/40) in G3, respectively.

CONCLUSIONSGastric neuroendocrine neoplasms occur mainly in the esophagogastric junction, and most of them were highly malignant. The coincidence rate of preoperative and postoperative pathological diagnosis for primary gastric neuroendocrine neoplasms is low. Therefore, it should be very cautious when diagnosis of this disease is made in a preoperative biopsy.