Solitary liver involvement by direct invasion in gastric adenocarcinoma

Background
Gastric adenocarcinoma is among the most prevalent malignancies worldwide, with about 1 million new cases annually and ranking as the fifth leading cause of cancer mortality. Advanced disease frequently presents with metastatic spread, most commonly to the liver, occurring in up to 48% of cases, mainly via hematogenous dissemination. In contrast, direct contiguous invasion of adjacent organs, including the liver, is uncommon and usually associated with locally advanced T4 tumors, where the primary lesion penetrates the serosa to infiltrate neighboring structures. This pattern occurs in roughly 10–15% of advanced gastric cancers and is often linked to limited surgical resectability and poor prognosis, with median survival below 12 months in untreated patients. Genomic studies have identified alterations in TP53, CDH1, and PIK3CA that promote tumor progression and metastatic behavior, supporting targeted therapies. Unlike multifocal hematogenous metastases, contiguous hepatic involvement may allow curative resection in selected patients, with reviews reporting 5-year survival of 24–25% after hepatectomy for solitary lesions.
Methodology
We report the case of a 68-year-old woman presenting to the emergency department with acute hematemesis. Urgent upper gastrointestinal endoscopy revealed an ulcerated lesion in the gastric body. Endoscopic biopsies confirmed moderately differentiated adenocarcinoma. Staging used contrast-enhanced computed tomography (CT) to assess local tumor extension and distant spread. Laboratory investigations included complete blood count, liver function tests, and tumor markers, including carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9). Case management was discussed within a multidisciplinary team.
Results
Histological analysis demonstrated invasive adenocarcinoma with glandular architecture and moderate differentiation, positive for cytokeratin expression. CT revealed a solitary hepatic lesion in the left lobe measuring approximately 4 cm, directly adjacent to and infiltrating the posterior gastric wall, consistent with contiguous invasion. No vascular involvement, multifocal liver lesions, peritoneal carcinomatosis, distant metastases, or nonregional lymphadenopathy were seen. Tumor markers showed elevated CEA (12.5 ng/mL) with normal alpha-fetoprotein. The patient had ECOG performance status 1 and no significant comorbidities.
Conclusions
This case highlights the rare occurrence of solitary hepatic involvement via contiguous invasion in gastric adenocarcinoma and underscores the importance of prompt endoscopic and radiologic evaluation in patients with upper gastrointestinal bleeding. While systemic chemotherapy remains standard for advanced disease, emerging evidence supports conversion surgery after neoadjuvant chemoimmunotherapy in selected patients with organ invasion. Multidisciplinary strategies, including hepatectomy for limited disease, may improve long-term outcomes. Long-term surveillance remains essential due to the risk of late metastatic recurrence.