S3659 Primary Gastric Squamous Cell Carcinoma With Concurrent H. pylori Infection and Colonic Metastasis

Abstract

Introduction: Primary gastric squamous cell carcinoma (PGSCC) is a rare, aggressive, malignancy that cannot be distinguished from other gastric malignancies clinically and therefore, requires EGD with biopsy and pathology. H. pylori infection is a known risk factor for gastric malignancies but, only one case has been reported with an association between the two. Case Description/Methods: 66-year-old Hispanic male, with no significant medical, family, or social history presented to the hospital with syncope. Further history revealed three weeks of melena, fatigue, exertional dyspnea, and 50 lb weight loss. Upon evaluation, the patient was found to have HGB of 3.2. CT abdomen with contrast showed a mass in the antrum of the stomach, most prominent posteriorly and around the greater curvature. EGD revealed normal esophagus and a 15 cm, oozing, fungating, and partially circumferential gastric mass. It was located in the antrum, involving the entire posterior wall with extension into the greater curvature. The gastric mass was 5 cm below the GE junction, without evidence of esophageal involvement. Biopsy of the mass revealed poorly differentiated squamous cell carcinoma and Helicobacter pylori infection. Colonoscopy then revealed a 4 cm lesion near the splenic flexure which was confirmed to also be poorly differentiated squamous cell carcinoma. The patient was placed on triple therapy for his H. pylori infection. PET scan showed known gastric and colonic mass with multiple enlarged and hypermetabolic perigastric and retroperitoneal lymph nodes consistent with metastasis. He was seen by oncology and started on systemic chemotherapy (Figure 1). Discussion: PGSCC is a rare form of gastric malignancy accounting for roughly 0.2% of primary gastric cancer reported. Compared to the more common gastric adenocarcinoma, SCC tends to be more aggressive with poorer outcomes. Unfortunately, the pathogenesis remains obscure, making early detection difficult. Our case was associated with H. pylori infection which is one of the most significant risk factors for the development of gastric cancer due to the chronic inflammation caused by infection. Additionally, metastasis to the colon is exceptionally rare with most cases metastasizing to liver, peritoneum, lung and bone. Further investigation and studies are needed to understand this rare disease.Figure 1.: Primary gastric tumor (left panel), submucosal colonic mass (right panel).