# Hepatoid Adenocarcinoma of the Stomach Combined With Gastric Neuroendocrine Carcinoma: A Case Report

## TL;DR

A rare case of aggressive stomach cancer combined with neuroendocrine features was treated with immunotherapy and targeted therapy, showing improved survival and quality of life.

## Contribution

This case report presents a novel treatment approach using Lenvatinib plus Envafolimab for a rare gastric cancer subtype.

## Key findings

- The patient's cancer showed rapid recurrence and poor response to conventional chemotherapy.
- Switching to Lenvatinib plus Envafolimab improved survival and quality of life in this case.
- The case highlights the potential of immunotherapy and targeted therapy for this aggressive cancer subtype.

## Abstract

Both hepatoid adenocarcinoma of the stomach (HAS) and gastric neuroendocrine carcinoma (NEC) are rare subtypes of gastric cancer, characterized by aggressive behavior and poor prognosis, for which no definitive treatment regimen has been established to date. A 56‐year‐old male was diagnosed with HAS combined with NEC, accompanied by perigastric lymph node and liver metastases. Initially, he received EP chemotherapy, which was subsequently switched to a regimen of capecitabine plus oxaliplatin due to insufficient therapeutic response. Ultimately, the treatment was transitioned to a combination of immunotherapy and targeted therapy with Lenvatinib plus Envafolimab, owing to the development of capecitabine intolerance. The optimal management of this disease remains undefined, and conventional chemotherapy often results in suboptimal outcomes. However, in this case, the treatment with Lenvatinib plus Envafolimab appears to be an effective strategy for prolonging survival time and improving quality of life. Further experimental and clinical investigations are warranted to validate these findings and substantiate this therapeutic hypothesis.

(a) Gastric resection (52‐year‐old man, initial presentation): poorly differentiated carcinoma, consistent with hepatoid adenocarcinoma with neuroendocrine differentiation. Carcinoma invaded the muscularis propria, and vascular tumor emboli were identified. (b, c) Hepatic resection specimen: poorly differentiated carcinoma was detected, representing metastatic hepatoid adenocarcinoma. A small number of cancer cells were found with perineural invasion, focal perineural invasion correlates with the patient's rapid local recurrence and underscores the rationale for adding lenvatinib/envafolimab after failure of cisplatin‐based and capecitabine‐containing regimens.