Two independent families with strongly suspected hereditary diffuse gastric cancer based on the probands' endoscopic findings

Detection of multiple signet ring cell carcinomas using texture and color enhancement imaging led to a diagnosis of hereditary diffuse gastric cancer

Hereditary diffuse gastric cancer (HDGC) is an autosomal dominant cancer caused by CDH1 mutation. HDGC causes multiple signet ring cell carcinomas (SRCCs) throughout the stomach. Few reports exist on the endoscopic findings during screening endoscopy, leading to the diagnosis of HDGC in its early stages. Recently, a new image-enhancement endoscopy technique, texture and color enhancement imaging (TXI), has been developed to improve the visibility of early gastric cancer. To the best of our knowledge, the use of TXI leading to HDGC diagnosis has not been reported. In this report, TXI contributed to the diagnosis of HDGC, and the patient was treated with total gastrectomy. A 27-year-old woman with a family history of gastric cancer underwent esophagogastroduodenoscopy, which revealed two pale lesions in the lower body of the stomach. Histological examination of the biopsy specimen revealed SRCC and the patient was referred to our hospital for treatment. Multiple lesions were found in the lower body using TXI, and a targeted biopsy confirmed other SRCCs. We suspected her disease to be HDGC, and the patient underwent a total gastrectomy. Histopathology showed multiple SRCCs (>60), but no lymph node metastases. Genetic testing revealed CDH1 mutations. The final pathological stage of the tumor was pT1a(m) N0M0 Stage I. TXI may be helpful in detecting multiple SRCCs in patients with HDGC. Endoscopists should be aware of HDGC, and careful investigation of the entire stomach is required for patients with diffuse-type gastric cancer before treatment.

Hereditary Diffuse Gastric Cancer Treated by Prophylactic Total Gastrectomy

We herein report a rare case of hereditary diffuse gastric cancer in a Japanese man. A 41-year-old man underwent esophagogastroduodenoscopy which revealed a small gastric erosion. Biopsy specimens showed signet ring cell carcinoma, and endoscopic submucosal dissection was performed. The patient's elder sister had died of gastric cancer at 38 years old. Considering the family history, a genetic test was conducted and revealed a CDH1 germline mutation. Although no carcinomatous lesion was detected endoscopically, prophylactic total gastrectomy was performed. The resection specimen showed seven microlesions of signet ring cell carcinoma confined to the lamina propria mucosae.

Invasive stratified mucin-producing carcinoma of the colorectum: expanding the morphologic spectrum of large bowel cancer

BACKGROUND

Invasive stratified mucin-producing carcinoma is a recently recognized adenocarcinoma with distinctive features. It was first described in the cervix but similar tumors have since been reported in the penis, anus and prostate. In the gastrointestinal tract, the phenomenon of epithelial stratification has an interesting embryologic morphogenesis. Gastrointestinal mucosa starts off as nascent columnar epithelium that is subsequently patterned to confer regional specific functions. However, in disease states, normal architectural patterning can be disrupted by aberrant differentiation. Given this background and the phenotypic plasticity of neoplastic cells, we were interested in ascertaining whether invasive stratified mucin-producing carcinoma occurs in the colorectum.

METHODS

This was a retrospective study of all 584 cases of colorectal carcinoma accessioned at our institution over a 2-year period (January 2021- December 2022). Cases were analyzed to determine which fulfilled the criteria for invasive stratified mucin-producing carcinoma.

RESULTS

There were 9 cases of colorectal invasive stratified mucin-producing carcinoma-one pure form and 8 mixed. They showed the classic colorectal (CK20 + , CDX2 + , CK7-) immunostaining profile but, based on various morphologic criteria, they could be distinguished from conventional adenocarcinoma NOS, mucinous, signet ring cell, medullary, goblet cell and undifferentiated carcinomas. About half the cases were MLH1/PMS2 deficient and BRAF &/or PIK3CA mutated, which aligns with the hypermutated phenotype.

CONCLUSIONS

Colorectal invasive stratified mucin-producing carcinoma appears to be a real entity, best recognized in its early stages. It appears to be a high-grade carcinoma. With tumor progression, it evolves into a mucinous adenocarcinoma with a proclivity towards signet ring cells. In summary, the study of this tumor, particularly in its early stages, provides useful clues to further understanding the biology and progression of large bowel cancer. Further studies are required to learn more about this tumor.

Hereditary Diffuse Gastric Cancer

Hereditary diffuse gastric cancer (HDGC) is a dominantly inherited cancer syndrome characterized by a high incidence of diffuse gastric cancer (DGC) and lobular breast cancer (LBC). HDGC is caused by germline mutations in 2 genes involved in the epithelial adherens junction complex, CDH1 and CTNNA1. We discuss the genetics of HDGC and the variability of its clinical phenotype, in particular the variable penetrance of advanced DGC and LBC, both within and between families. We review the pathology of the disease, the mechanism of tumor initiation, and its natural history. Finally, we describe current best practice for the clinical management of HDGC, including emerging genetic testing criteria for the identification of new families, methods for endoscopic surveillance, the complications associated with prophylactic surgery, postoperative quality of life, and the emerging field of HDGC chemoprevention.

Lifestyles, genetics, and future perspectives on gastric cancer in east Asian populations

The prevalence of gastric cancer (GC) differs among regions worldwide, with the highest occurrence in east Asia. Thus, its etiology, with respect to ethnic background, environmental factors, and lifestyles, is also thought to differ essentially. In addition, etiology of GC is speculated to be changing due to the recent decrease in the Helicobacter pylori (H. pylori) infection in Japan. State-of-the-art somatic/germline cancer genomics has clarified the etiologies of gastric carcinogenesis. In this review article, we summarize past and present milestones in our understanding of GC achieved through genomic approaches, including a recent report that revealed higher-than-expected frequencies of GCs attributed to east Asian-specific germline variants in ALDH2 or CDH1 in combination with lifestyles. Based on this updated knowledge, we also discuss the possible impact of and high-risk approaches for GCs in the upcoming "H. pylori-negative era."

Inherited Predisposition to Gastric Cancer

Approximately 10% of patients with gastric cancer show familial aggregation and up to 3% are related to an inherited cancer syndrome. There are multiple germline pathogenic variants and cancer syndromes associated with an increased risk of gastric cancer. Appropriate assessment of familial and genetic risk may allow a personalized approach to gastric cancer prevention through screening and risk-reducing surgeries. The ability to better identify carriers with pathogenic genetic variants associated with gastric cancer before a diagnosis of cancer requires effective genetic risk assessment and testing, followed by optimal screening and surveillance recommendations to further reduce the morbidity and mortality.

Case series of three patients with hereditary diffuse gastric cancer in a single family: Three case reports and review of literature

BACKGROUND

Hereditary diffuse gastric cancer (HDGC) is a familial cancer syndrome often associated with germline mutations in the CDH1 gene. However, the frequency of CDH1 mutations is low in patients with HDGC in East Asian countries. Herein, we report three cases of HDGC harboring a missense CDH1 variant, c.1679C>G, from a single Japanese family.

CASE SUMMARY

A 26-year-old female (Case 1) and a 51-year-old male (father of Case 1), who had a strong family history of gastric cancer, were diagnosed with advanced diffuse gastric cancer. After genetic counselling, a 25-year-old younger brother of Case 1 underwent surveillance esophagogastroduodenoscopy that detected small signet ring cell carcinoma foci as multiple pale lesions in the gastric mucosa. Genetic analysis revealed a CDH1 c.1679C>G variant in all three patients.

CONCLUSION

It is important for individuals suspected of having HDGC to be actively offered genetics evaluation. This report will contribute to an increased awareness of HDGC.