We report a case of a 71-year-old female with a primary cardiac tumor. The patient had undergone surgery for uterine cancer 10 years ago and presented to a nearby clinic complaining of dyspnea on exertion. Chest X-ray revealed cardiac enlargement, prompting further investigations, which revealed a massive tumor protruding into the left atrium and extending toward the outer wall of the left ventricle. The patient was referred to a cardiac surgery department for myocardial biopsy. The tumor biopsy confirmed a diagnosis of a vascular tumor. Due to the tumor's large size and the difficulty in achieving complete resection, a conservative approach was chosen as the patient expressed a preference for non-surgical treatment. This is an extremely rare case of a large primary cardiac tumor, and we report it accordingly.