Right Atrial Mass in a Young Patient With Pheochromocytoma: How useful is CMR

Description of Clinical Presentation: A 24-year-old male with biochemically confirmed pheochromocytoma presented with paroxysmal palpitations and labile blood pressure. Transthoracic echocardiography identified a right atrial mass attached to the interatrial septum, and patient was referred for comprehensive cardiac magnetic resonance (CMR) to characterize the lesion and guide management.

Diagnostic Techniques and Their Most Important Findings: The CMR protocol included cine balanced SSFP for anatomy and function, black-blood T1- and T2-weighted imaging with edema/fat suppression, first-pass perfusion after gadolinium, and late gadolinium enhancement (LGE) for tissue characterization. A lobulated mass measuring 5.0 cm × 5.3 cm × 3.4 cm was seen at the interatrial septum. The lesion showed marked T2/STIR hyperintensity and isointense T1 signal, consistent with a water-rich, hypercellular mass. First-pass perfusion demonstrated intense, early, and diffuse intralesional enhancement, indicating pronounced hypervascularity. LGE revealed heterogeneous, diffuse enhancement with interspersed nonenhancing foci, compatible with fibrous stroma and patchy necrosis. No signal dropout on fat-suppressed sequences and no macroscopic hemorrhagic components were evident. Cine imaging documented preserved biventricular size and function, no dynamic obstruction, and no significant flow limitation at the venae cavae. Taken together, these features strongly supported a hypervascular cardiac tumor and argued against thrombus, which typically shows absent first-pass perfusion and no LGE. Compared with atrial myxoma, the lesion’s avid perfusion, higher T2 signal, and more heterogeneous enhancement pattern were more suggestive of a neuroendocrine tumor.

The patient underwent multidisciplinary evaluation and surgical planning emphasizing vascular control due to the lesion’s hypervascularity. Cardiac paragangliomas are rare neuroendocrine tumors that may be catecholamine-secreting and can occur in association with extra-cardiac pheochromocytomas, especially in younger patients. Right atrial involvement, including attachment to the interatrial septum, is a recognized although uncommon presentation of cardiac paraganglioma. Histopathology following surgical excision established the final diagnosis of a cardiac paraganglioma.

Learning Points from this Case:

• In young patients with pheochromocytoma, a right atrial mass with T2/STIR hyperintensity, isointense T1, intense first-pass perfusion, and heterogeneous LGE on CMR is highly suggestive of cardiac paraganglioma.


• A structured CMR mass protocol (cine, T1/T2 with fat/edema suppression, first-pass perfusion, and LGE) is critical to distinguish tumor from thrombus and to differentiate paraganglioma from other neoplasms such as myxoma or metastasis.


• Hypervascularity on perfusion and heterogeneous LGE are key discriminators that influence surgical planning, emphasizing the value of CMR in preoperative risk stratification.

Tecidual Characterization
First-pass Perfusion
Cines