This article presents the case of a 24-year-old woman with Poland syndrome who developed primary right atrial cardiac angiosarcoma. The patient presented to the hospital with dyspnea and chest pain, and imaging studies revealed a large mass attached to the right atrium. Urgent surgery was performed to remove the tumor, and the patient underwent adjuvant chemotherapy afterward. Follow-up exams showed no signs of the tumor or any complications from treatment. Poland syndrome is a rare congenital disorder characterized by the absence of unilateral large pectoral muscle, ipsilateral symbrachydactyly, and other malformations of the anterior chest wall and breast. Although the condition does not predispose patients to malignancy, different pathologies can be seen in these patients due to the unknown etiology of the syndrome. Primary right atrial cardiac angiosarcoma is a rare malignancy, and its coexistence with Poland syndrome has not been well established in the literature. This case report highlights the need to consider cardiac angiosarcoma as a possible diagnosis in patients with Poland syndrome who present with cardiac symptoms.