Cardiac myxomas are the most common primary cardiac neoplasms presenting as an endocardial mass occupying cardiac chambers. In majority of cases, myxomas are seen attached to the IAS and less frequently seen in ventricles. Around 75% of myxomas are seen in left atrium and 20% seen in right atrium. Cardiac myxomas usually present with obstructive constitutional symptoms such as fever, chills and lethargy, and in around 20% patients, cardiac myxomas produce no symptoms. However, in 30–40% patients, cardiac myxomas present with embolic phenomenon with clinical manifestation according to the location of the mass, the left or right side of heart. Left-sided myxomas may present with fatal cardiovascular embolic events such as stroke and coronary embolization or with complete obstruction of mitral or aortic valve. It is imperative that a diagnosis of cardiac myxoma be made using advanced imaging techniques such as echocardiography, CTA or CMR [2, 3].

Typically, cardiac myxomas present as solid mass lesions with heterogeneous enhancement on contrast administration. Cardiac myxomas can have a heterogenous appearance reflecting hemorrhage, necrosis, fibrosis or calcification and pose challenges in diagnosis and treatment. An intracardiac cystic mass with heterogenous post-contrast enhancement can have a wide list of differential diagnosis such as hydatid cyst, IAS aneurysm, coronary artery aneurysm, intramural hematoma of LA, sarcomas, hemangiomas, hemangioendotheliomas, bronchogenic cysts and rarely myxomas. It is difficult to establish a firm diagnosis due to overlapping imaging features; hence, histopathological examination is the way forward for further management and prognosis of the patient. It is necessary to adapt an aggressive diagnostic approach in case of a cystic cardiac mass to unmask stealth malignant lesions such as sarcomas which can present as benign appearing mass lesions on imaging 11,12,13,14,15].

This case illustrates a rare cystic form of atrial myxoma and highlights the importance of considering this condition when diagnosing apparently cystic intracardiac mass. It underscores the significance of CMR in evaluating these masses and the value of imaging techniques in distinguishing myxomas from other potential causes of intracardiac masses. Due to their structural similarities, accurately diagnosing LA cystic masses using preoperative imaging is challenging. Failure to remove these masses may lead to major complications such as stroke, rupture, and hemodynamic alterations. Therefore, surgical excision of a cystic LA mass is justified to establish a definitive diagnosis and prevent potential complications.