Cardiac paragangliomas (PGLs) are rare neuroendocrine tumors, and data regarding the features of nonfunctioning PGLs are limited. These tumors are extensively vascularized and have high risk of hemorrhage for surgery and even biopsy. Differential diagnosis including biochemical analysis of these PGLs is important for further management. In this case report, we present the clinical, laboratory, imaging, and radionuclide presentations of a rare primary nonfunctioning cardiac PGL with a coronary aneurysm. Echocardiography initially showed a large echogenic mass in the left atrioventricular groove. The mass presented a diffuse hyperenhancement pattern with a central perfusion defect on contrast echocardiography. The tumor enclosed the left coronary artery from the coronary orifice, and an aneurysm was found in the left circumflex artery, with significantly increased flow velocity. These echocardiographic features and its susceptible location are indicative of the presence of a cardiac PGL. Although all biochemical evaluations of catecholamines from blood and urine samples were negative, positron emission tomography and scintigraphy finally confirmed the diagnosis of a primary cardiac PGL. Therefore, when imaging features are indicative of the presence of PGLs, the implementation of radionuclide imaging for final diagnosis is required even if the biochemical results are negative. Recognizing these uncommon Doppler and contrast echocardiographic characteristics is important for early diagnosing these nonfunctioning PGLs.

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