2668 Pleural Effusion From an Unexpected Source!

Abstract

INTRODUCTION: Gastric adenocarcinoma (GAC) is a global health burden. It is the third-leading cause of cancer-related mortality. Diagnosis is often delayed given the non-specific symptoms attributed to this disease. Gastric cancer is well known to cause distant metastases to other organs. However, it is unusual for patients to develop malignant pleural effusion as a presenting manifestation. Our case illustrates a unique diagnosis of an occult GAC after initial presentation with shortness of breath that deemed to be due to a malignant pleural invasion by signet ring cell cancer of the stomach. CASE DESCRIPTION/METHODS: A 70-year-old woman presented with worsening dyspnea and orthopnea of 1-month duration. Her past medical history included asthma and hypertension. Initial evaluation revealed a saturation of 98% on room air with decreased breath sounds halfway up upon auscultation of the right lung. Chest x-ray demonstrated a moderate right pleural effusion. Thoracentesis was performed with removal of 1 L of amber-colored fluid. The cytological analysis revealed adenocarcinoma with signet ring cell features. Upper endoscopy showed an 8 cm irregular necrotic ulcer at the lesser curvature of the stomach. Pathology confirmed the presence of a moderately differentiated infiltrative signet ring cell adenocarcinoma. Giemsa stain revealed helicobacter pylori (HP). Immuno-histochemical stains were positive for CK 7, hMLH1, 2 and 6. A positron emission tomography showed evidence of metastasis in right pleural space and lumbar spine. The patient received triple therapy for HP and confirmed eradication as well as modified FOLFOX 6 therapy every two weeks. DISCUSSION: Gastric adenocarcinoma is the fifth most common cancer in the world. Helicobacter pylori is a well recognized underlying risk factor for GAC. Around 1-3% of patients infected with HP progress to develop GAC. Chronic infection in this setting results in hypochlorhydria that leads to atrophic gastritis and intestinal metaplasia followed by dysplasia and subsequent neoplasia. Malignant pleural effusion is a rare presenting manifestation of GAC accounting for only two percent of cases. In advanced stage GAC, common metastatic sites include distant lymph nodes, liver, peritoneum with rare metastasis to lungs, bone, brain, and leptomeningeal space. Our case was distinctive as the pleural effusion was the initial presentation of an occult GAC diagnosed after that. Prognosis of metastatic GAC remains poor because of limited effective therapies.