S6282 Hidden in Plain Sight: An Incidental Discovery of Gastric Leiomyosarcoma

Introduction: Gastric leiomyosarcomas are extremely rare tumors arising from the muscularis propria of the stomach. With the advent of immunohistochemistry, many tumors previously diagnosed as gastrointestinal stromal tumors (GIST) are now reclassified under leiomyosarcoma, making them account for less than 1% of all gastric tumors. In this case report, we present an unusual presentation of gastric leiomyosarcoma. Case Description/Methods: A 66-year-old woman with a past medical history of congestive heart failure (CHF), atrial fibrillation on apixaban, pulmonary hypertension, and chronic obstructive pulmonary disease (COPD). She presented to the emergency department with dyspnea on exertion and bilateral lower extremity edema and was admitted for the treatment of CHF exacerbation. Routine laboratory investigations revealed hypochromic microcytic anemia, with a hemoglobin level of 5.6 g/dL (baseline of 11.2 g/dL 5 months ago). A computed tomography (CT) of the abdomen and pelvis with contrast did not reveal any significant abnormalities but was limited due to the patient's body habitus and a large abdominal hernia. Esophagogastroduodenoscopy (EGD) revealed a large, ulcerated mass in the cardia of the stomach along with a large hiatal hernia. A biopsy of the mass confirmed the diagnosis of gastric leiomyosarcoma. Despite the patient’s elevated risk due to multiple comorbidities, overall risk-benefit analysis favors surgical intervention. Discussion: Our case highlights an incidental diagnosis of the tumor in a patient who initially presented with CHF exacerbation, possibly exacerbated by anemia secondary to chronic gastrointestinal bleeding from the tumor. The most common presentations of gastric leiomyosarcoma include nausea, vomiting, weight loss, upper gastrointestinal bleeding, and a palpable mass. Imaging and tissue diagnosis are crucial for accurate identification. CT imaging typically shows a large heterogeneous mass with peripheral solid enhancement and central areas of necrosis, hemorrhage, or degeneration. A tissue biopsy is required for definitive diagnosis. Unfortunately, there is limited data on the benefits of chemotherapy and radiotherapy for gastric leiomyosarcoma. Surgical resection remains the standard of treatment. Further research into the potential benefits of chemotherapy and immunotherapy could benefit patients like ours, where surgical intervention carries significant risks due to cardiovascular comorbidities.