Clinical characteristics of early neuroendocrine carcinoma in stomach: A case report and review of literature

Advances in Endoscopic Diagnosis and Treatment of Gastric Neuroendocrine Neoplasms

Gastric neuroendocrine neoplasms refer to a group of diseases that are relatively rare. They can be classified into three subtypes based on their clinical and histopathological features, and there are significant differences in diagnosis, treatment, and prognosis among the different subtypes. The incidence of gastric neuroendocrine neoplasms has been increasing globally in recent years with the localized disease being particularly evident. Gastrointestinal endoscopy is of irreplaceable importance for the diagnosis and management of g-NENs. Endoscopy with biopsy is the gold standard for the diagnosis of g-NENs. Ultrasound endoscopy can assess the depth of tumor invasion and the presence of lymphatic metastases, which is important for the development of treatment strategies. Meanwhile, for some small and low-risk lesions, endoscopic surveillance or endoscopic resection has satisfactory therapeutic results and prognosis. This means that even though the incidence has increased, advances in endoscopic techniques have allowed more patients to adopt a relatively conservative treatment strategy. However, the criteria for patients suitable for endoscopic surveillance or endoscopic resection remain controversial.

Endoscopic features of gastric neuroendocrine carcinoma

BACKGROUND AND AIM

The endoscopic features of gastric neuroendocrine carcinoma (G-NEC) have not been clarified; therefore, they were investigated in relation to clinicopathological findings.

METHODS

Consecutive patients with G-NECs who had undergone endoscopic or surgical resection at our institution between January 2005 and March 2022 were included in this retrospective study. The endoscopic and clinicopathological findings of the lesions were analyzed to provide information of diagnostic value. In addition, cases of gastric neuroendocrine tumor (G-NET) and common-type gastric adenocarcinoma treated in the same study period were identified to compare the endoscopic findings between each G-NEC versus G-NET, and G-NEC versus common-type gastric adenocarcinoma. Patients with common-type gastric adenocarcinoma were matched for age, sex, tumor size, and depth of tumor invasion in 1:3 ratio.

RESULTS

Among 15 patients with 15 G-NECs, submucosal tumor-like marginal elevation (87%), adherent white coat (67%), and ulceration with a distinct border (60%) were characteristic endoscopic findings in white-light images. Magnifying narrow-band imaging endoscopy revealed an absent microsurface (MS) pattern plus disrupted irregular microvessel (MV) in five (71%) of seven cases with evaluable MS and MV patterns. The area with an absent MS pattern plus disrupted irregular MV corresponded to the histological finding of NEC component in all five cases. These endoscopic features were all significantly more frequent in G-NECs than G-NETs (n = 22) or common-type gastric adenocarcinomas (n = 45).

CONCLUSIONS

These endoscopic features should be taken into consideration to increase the index of suspicion and to improve the accuracy of target biopsies for G-NEC.

Differences in clinicopathology and prognosis between gastroesophageal junctional and gastric non-cardiac neuroendocrine carcinomas: a retrospective comparison study of consecutive 56 cases from a single institution in China

Gastric neuroendocrine carcinoma (NEC), including mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN), is uncommon and differences in clinicopathological features and outcomes of NEC arising in various gastric regions remain elusive. We investigated 56 consecutive NECs identified among 3961 gastrectomies performed at our center between 2005 and 2021. We then compared clinicopathological characteristics and prognosis between gastroesophageal junctional (GEJ) NECs (N=39) and gastric non-cardiac NECs (N=17). No significant difference was found between the two groups in age, gender, tumor size, mixed non-neuroendocrine carcinoma component, MiNEN, NEC type, metastatic NEC component in lymph nodes, tumor infiltrating lymphocyte, lymph node metastasis, lymphovascular or perineural invasion, intestinal metaplasia in adjacent non-neoplastic mucosa, and expression of P53, PD-L1, TTF-1, HER2, and Ki-67. However, compared to gastric non-cardiac NECs, GEJ NECs displayed a significantly higher frequency of prevalence (2.79% versus 0.66%), pT3-T4 (92.3% versus 64.7%), advanced pathological stage (IIb-IV) (76.9% versus 47.1%), and a significantly lower 5-year overall survival rate (46.1% versus 73.1%) (P<0.05). The GEJ location was the only independent risk factor for overall survival. In stage-stratified comparisons, patients with stage II GEJ NEC demonstrated a significantly lower 5-year survival rate than those with gastric non-cardiac NEC at the same stage. Compared to non-NECs matched for age, gender, tumor location, and pathological summary stage, GEJ NEC was associated with significantly worse prognosis. In conclusion, GEJ NEC showed deeper invasion, more advanced pathological stages, and worse prognosis than gastric non-cardiac NEC. The findings provide pathologic evidence for individualized management strategies for patients with GEJ NEC. Future studies with larger samples are needed.

Label-free identification of early gastrointestinal neuroendocrine tumors via biomedical multiphoton microscopy and automatic image analysis

At present, early diagnosis and treatment is the most effective way to treat early gastrointestinal neuroendocrine tumors. Therefore, we attempted to carry out multiphoton imaging of early neuroendocrine tumors because of its ability to label-free image tissue microstructure at the cellular level. Imaging results show that this imaging technique can quickly identify the histopathological changes in mucosa and submucosa caused by tumor invasion. Furthermore, we performed automatic image analysis on SHG images and extracted two optical diagnostic features-collagen density and average intensity, and also found obvious differences in the density as well as average intensity of collagen fibers in tumor microenvironment using a series of quantitative analysis. These findings may further facilitate the development of multiphoton microscopic imaging technique for clinical use.