Abstract
This case report details a challenging instance of undifferentiated/unclassified cardiac sarcoma in a 28-year-old female, presenting with diverse symptoms like muscle weakness, shortness of breath, and hemoptysis. Diagnostic hurdles led to an initial misdiagnosis of granulomatosis with polyangiitis before discovering a sizable left atrial mass, ultimately diagnosed as high-grade undifferentiated/unclassified sarcoma. Despite initial surgical intervention, the patient's condition worsened, underscoring the complexities in managing such cases involving cardiac sarcomas. This case emphasizes the diagnostic complexities associated with primary cardiac sarcomas, particularly the challenges in achieving accurate diagnoses and formulating effective treatment strategies.