# CDH1 gene mutation, a challenging surgical topic: Case report and literature review

## TL;DR

This paper discusses a case of a young man with a CDH1 gene mutation who underwent surgery to prevent gastric cancer, highlighting the importance of genetic testing and surgical management for hereditary diffuse gastric cancer.

## Contribution

The paper presents a case report and literature review emphasizing the role of CDH1 gene mutation in hereditary diffuse gastric cancer and the need for prophylactic surgery.

## Key findings

- A 31-year-old male with CDH1 gene mutation underwent prophylactic total gastrectomy and D1 lymphadenectomy.
- Post-surgery pathology revealed small foci of signet ring cells, confirming the need for early surgical intervention.
- Follow-up gastroscopy is not recommended for CDH1 carriers due to high risk of false negatives.

## Abstract

Gastric cancer is one of the top 5 cancers worldwide. Most gastric cancers are classified as sporadic with the exception of around 3 % that are associated with specific syndromes or genes. Hereditary diffuse gastric cancer is a very rare type of gastric cancer, associated with loss of function of a tumor suppressor gene CDH1 which has a high penetrance that can reach 90 % over a lifetime.

Here we present the case of a 31 years old male patient carrying the CDH1 gene who presented for prophylactic total gastrectomy and D1 lymphadenectomy followed by a roux en y esophago-jejunostomy for digestive tract reconstruction. The patient had a preoperative negative gastroscopy for gastric cancer. On final pathology, few 2 mm foci of signet ring cells involving the lamina propria (T1a) were identified.

Randomized clinical trial data concerning HDGC is lacking. Individuals who meet the genetic testing criteria developed by the IGCLC, testing should be obtainable from the legal age of consent that range from 16 to 18 years of age. CDH1 is the main gene that is tested. The mainstay treatment of choice for HDGC is total gastrectomy and Roux-en-Y esophago-jejunostomy in asymptomatic patients but should only be undertaken after baseline endoscopy.

Genetic testing for CDH1 should be carried in high-risk populations. Due to its high penetrance, any person carrying the CDH1 gene should be managed by a prophylactic gastrectomy and D1 lymphadenectomy with close follow up for any future breast neoplasm.

•Hereditary diffuse gastric cancer is a very rare type of gastric cancer, associated with loss of function of a tumor suppressor gene CDH1 which has a high penetrance that can reach 90 % over a lifetime.•Prophylactic total gastrectomy with D1 lymphadenectomy is the only management required post detection of the CDH1 gene.•Follow up gastroscopy has no place in the management of people carrying this gene because it is operator dependent and false negative gastroscopy can be easily reported due to small foci of cancer. Gastroscopy is only used in a preoperative setting in order to rule out any advance gastric cancer which can affect the surgical management of the case.•The penetrance of such gene for the development of lobular breast cancer is inferior to the penetrance seen in gastric cancer, thus follow up by yearly mammography and breast ultrasound is an acceptable option post detection of the gene and prophylactic total gastrectomy and lymphadenectomy.

Hereditary diffuse gastric cancer is a very rare type of gastric cancer, associated with loss of function of a tumor suppressor gene CDH1 which has a high penetrance that can reach 90 % over a lifetime.

Prophylactic total gastrectomy with D1 lymphadenectomy is the only management required post detection of the CDH1 gene.

Follow up gastroscopy has no place in the management of people carrying this gene because it is operator dependent and false negative gastroscopy can be easily reported due to small foci of cancer. Gastroscopy is only used in a preoperative setting in order to rule out any advance gastric cancer which can affect the surgical management of the case.

The penetrance of such gene for the development of lobular breast cancer is inferior to the penetrance seen in gastric cancer, thus follow up by yearly mammography and breast ultrasound is an acceptable option post detection of the gene and prophylactic total gastrectomy and lymphadenectomy.