A Rare Case of Isolated Cardiac Sarcoidosis With Negative Biopsy: Diagnosis by Clinical Criteria.

Cardiac sarcoidosis (CS) is a potentially life-threatening condition that can cause sudden, fatal conduction abnormalities, arrhythmias, and heart failure. The diagnosis of CS is challenging due to nonspecific symptoms and an unclear diagnostic criterion. Although biopsy is the gold standard method, the sensitivity of biopsy is low. About a portion of CS cases are detected through imaging. A unique aspect of our case is that our definitive diagnosis was made based on clinical and imaging criteria alone despite a negative biopsy. Our diagnosis was confirmed further on follow-up with improvement in cardiac function on imaging after a treatment course with corticosteroids. This case highlights the need to have a broad differential and more awareness of this rare etiology and the value of clinical criteria to make a definitive diagnosis.