S6431 Simultaneous Gastric and Distal Esophageal Squamous Cell Carcinoma: A Rare Dual Malignancy

Introduction: Squamous cell carcinoma (SCC) is common in the esophagus but rare in the stomach, where adenocarcinoma predominates. Simultaneous primary SCCs of the distal esophagus and stomach are considerably uncommon, resulting in diagnostic therapeutic challenges. Differentiating between synchronous primaries and metastatic spread is critical, as management strategies and prognoses differ significantly. Case Description/Methods: A 63-year-old woman with a history of tobacco use presented with progressively worsening postprandial nausea, non-bloody emesis, pyrosis, and unintentional weight loss of 30 pounds over a period of 3 months. She denied dysphagia, odynophagia, melena, hematochezia, or abdominal pain. There was no family history of gastrointestinal malignancy. Esophagogastroduodenoscopy revealed a fungating, submucosal, polypoid mass involving approximately one-third of the distal esophageal lumen, extending from 34 cm from the incisors to the gastroesophageal junction at 38 cm. This lesion appeared contiguous with a 5 cm mass centered in the gastric cardia and proximal stomach. Biopsies from both sites confirmed well-differentiated SCC. Discussion: This case highlights a rare presentation of synchronous SCC involving both the distal esophagus and proximal stomach. While SCC is a known consequence of chronic tobacco or alcohol exposure, gastric involvement is especially rare and usually metastatic rather than primary. In this patient, the contiguous nature of the tumors raised suspicion for either direct local extension or field cancerization. Histologic similarities between the lesions adds complexity to distinguishing synchronous primary tumors from extension of a single malignancy. Prompt recognition of this unusual presentation is critical for staging accuracy, prognosis determination, and treatment planning. Thorough endoscopic and pathologic should be included in evaluation in patients with upper gastrointestinal symptoms and risk factors, even in the absence of classic dysphagia or bleeding.