Cardiac myxoma is the most frequent primary tumor of the heart. However, it is rarely associated with congenital cardiac anomalies such as atrial septal defect in the literature. We present a 24-year-old woman presented with progressive shortness of breath and finally diagnosed as a pedunculated mobile left atrial myxoma and concomitant occurrence of an ostium secundum type atrial septal defect. The mass was successfully excised, and atrial septal defect was safely repaired with pericardial patch. The patient is currently well after surgery. Atrial myxoma should be considered in the differential diagnosis when patients present with neurological consequences of systemic embolization.

Myxoma is the most common type of primary tumors of the heart.1,2 It is usually benign in nature, and commonly occurs between the third and the sixth decade of life. Approximately 75% of myxomas originate from the left atrium from the limbus fossae ovalis, and more than 90% are solitary.1,2 More importantly, myxomas are quite infrequently associated with congenital cardiac anomalies such as atrial septal defect.3-5 Cardiac myxoma can produce a wide spectrum of systemic findings including systemic and pulmonary embolism, and intracardiac obstruction.6-9 The neurological consequences of systemic embolization include transient ischemic attacks, stroke, seizures, and syncope.9 Mobile and/or pedunculated left atrial myxomas may prolapse to various degrees into the mitral valve orifice, infrequently resulting in obstruction of AV blood flow and mitral regurgitation. Therefore, the signs and symptoms of myxomas often mimic those of mitral valve disease. In this report, we describe a patient who had a pedunculated mobile myxoma in the left atrium associated with an ostium secundum type atrial septal defect.

A 24-year-old Bangladeshi female student was evaluated in the medicine outpatient door for progressive shortness of breath on exertion and palpitations for 3 months. But she denied any fever, cough, chest pain, hemoptysis and weight loss. On her physical examination, there was a grade 3/6 systolic ejection murmur that was most prominent at the left second intercostal space. An ECG recording showed normal sinus rhythm with hook-like notch or slur on the R wave in in the inferior limb leads: II, III, and aVF (Crochetage sign) (Figure 1). Chest X-ray showed normal cardiothoracic ratio. Laboratory tests were nonspecific and nondiagnostic. Two-dimensional transthoracic echocardiogram showed a small myxomatous mass (8 mm×7 mm) attached at the basal part of AML on LA side. There is minimal prolapse of AML with trivial MR. There is a defect involving secundum part of IAS (28 mm× 27 mm) with left to right shunt with dilated RA and RV. PASP is 46 mm Hg (Figure 2) suggestive of large ostium secundum ASD with suspected left atrial myxoma.

Figure 1: 12 lead ECG of the patient showing notch over the R wave in lead II, III, and aVF (Crochetage sign) (Black arrow)

Transesophageal doppler echocardiography showed an inhomogeneous, contractile, oscillating mass (14 mm×12 mm) is seen attached to the base of AML. RA and RV are dilated. There is an echo drop out area (18 mm) in the IAS at the level of fossa ovalis with laminar flow LA to RA shunt. IVS and IAS are intact. No thrombus or vegetation is seen. (Figure 3).

Figure 2 and Figure 3: Two-dimensional transthoracic echocardiogram showing a small myxomatous mass (8 mm×7 mm) attached at the basal part of AML on LA side and Transesophageal doppler echocardiography showing an echo drop out area (18 mm) in the IAS at the level of fossa ovalis with laminar flow LA to RA shunt.

She was referred to cardiothoracic surgeon where after proper counselling decision for surgery was made. Median sternotomy done, thymus dissected, pericardiotomy done, pericardium taken. CPB started. Heart arrested in diastole. Os ASD was found and atrial myxoma was seen at the basal part of the atrial side of AML. Removal of LA myxoma was done and ASD ostium secundum was closed with pericardial patch. LA mass was sent for histopathology. Chest was closed in layers keeping the mediastinal drain tube and RA, RV pacing wire in situ. Post operative echo cardiography showed no residual ASD flow and no residual LA mass with minimal pericardial effusion. LVEF was 68% and PASP was 25 mm of Hg. Later histopathology from LA mass revealed under a microscope, they feature characteristic round, oval, polygonal, stellate (star-shaped), or fusiform "lepidic" myxoma cells with bland, uniform nuclei, light pink cytoplasm, and distinct nucleoli embedded in an abundant, loose myxoid (mucopolysaccharide-rich) stroma. (Figure 4).

Figure 4: Histopathology from LA mass showing myxoma cells embedded in an abundant, loose myxoid stroma (Black arrow)

Primary cardiac tumors (CT) are rare. Of these, myxomas are the most common one[1,2]. The high portion of myxomas occurs in the left atrium, usually begins interatrial septum (fossa ovalis) and grows into the atrium [1,2]. But, they can also originate from the posterior atrial wall, the anterior atrial wall or the atrial appendage. The mass may protrude through the mitral valve into the left ventricle and obstruct the left ventricular inflow in diastole. Our patient had a left atrial myxoma attached to the basal part of AML of the left atrium, protruding towards the left ventricle without obstructing mitral valve orifice in diastole. Also, myxomas are very infrequently associated with congenital cardiac anomalies. Only in a few reports, myxoma has been reported with atrial septal defect [3-5]. We reported rare case of atrial myxoma with an ostium secundum type atrial septal defect. Clinical presentation may help in differentiating cardiac mass aetiology [10]. The majority of cardiac myxoma may produce the symptoms and signs of heart diseases. The clinical manifestations depend on their size and location; dyspnea is the most common manifestation in up to 80% of patients. The patients can also present with other cardiac symptoms such as chest pain, palpitation, and syncope6 Cardiac myxoma may be a source of emboli to the central nervous system and elsewhere in the vascular tree. Embolization is one of the critical complications of myxoma and occurs in about 30% to 40% of the patients. The site of embolism is dependent upon the location and the presence of an intracardiac shunt. In most cases, cardiac tumors have thrombi on their sur faces, and both thrombi and necrotic tumoral particles may cause systemic and pulmonary embolization. The neurological signs or symptoms may occasionally be the first or only clinical manifestation of a cardiac tumor as in our case [9]. An embolic stroke without evidence of cerebrovascular disease, particularly in the presence of sinus rhythm, should raise the suspicion of cardiac myxoma. Also, there appears a conflict regarding therapeutic approaches of embolic stroke; if thrombus causes embolization, thrombolysis may be useful, on the contrary, if tumoral particles lead to embolization, the patient will not benefit from thrombolytic therapy and even would be vulnerable to the side effects of thrombolysis. Non-invasive imaging remains the mainstay for the differential diagnosis. Transthoracic echocardiography (TTE) represents the first approach, while Transesophageal echocardiography (TEE) allows higher spatial resolution. Real-time volume-rendered three-dimensional echocardiography and post-processed data from multiplanar reconstructions further improve the diagnostic accuracy. Mass size and morphology, attachment site, extension, and mobility may be evaluated. Typically, myxomas are solitary, polypoid, pedunculated, and oval-shaped with a smooth or gently lobulated surface. They are generally located in LA, arising from the fossa ovalis [11,12]. On the contrary, thrombi are often multiple, of various size, and may occur in different sites. Typically, they appear as sessile, iso-/hyperechoic masses with defined margins and variable mobility [12]. Thrombus shrinkage is expected following anticoagulation, while myxomas usually grow over time [13]. However, there are reports of thrombi that do not dissolve with anticoagulation [14]. and myxomas that show no tendency to grow [15]. Cardiovascular MRI has high diagnostic accuracy.16 In the setting of a mass related to an implanted cardiac device, metal artefact may limit the diagnostic capability of this modality. In this setting, advanced imaging techniques should be used to improve image quality.13 Usually, fresh thrombi are hyperintense on T1 and T2 sequences, while chronic thrombi are iso-/hypointense. Similarly, myxomas are T1-isointense, but T2-hyperintense. First-pass perfusion, LGE, and post-contrast in version time (TI) scout sequences increase the discriminative power. Thrombi are avascular masses and therefore do not typically enhance on FPP and LGE sequences. Rare exceptions are justified by neovascularization of chronic thrombi. Myxomas may show some enhancement on FPP and LGE, corresponding with regions rich with myxomatous tis sue and focal inflammation. Nevertheless, these features are markedly more frequent in malignant tumors. Therefore, a negative FPP/LGE is inconclusive to exclude a myxoma. Lastly, thrombi usually show a typical TI scout pattern (hyper-/isointensity with short TI and hypointensity with long TI), which is exceptional in tumours.12 Coronary angiography is indicated to demonstrate the vascular supply to tumor and to exclude any underlying occult coronary artery disease. Surgery for atrial myxoma is the treatment of choice and helps in avoiding the occurrence of complications. After surgical removal of myxomas, patients usually remain symptom-free and have a normal lifespan.18 In our patient, diagnostic certainty was obtained only after surgical removal of the mass by histological examination.

The coexistence of left atrial myxoma and ostium secundum ASD in a young lady is an exceptionally rare clinical entity. This case highlights the importance of comprehensive echocardiographic evaluation in a patient with congenital heart disease, as associated intracardiac pathologies may be overlooked. Early recognition of this unusual association is crucial because atrial myxoma carry significant risk of embolization, intracardiac obstruction, and sudden cardiac complications. Prompt surgical excision of myxoma along with simultaneous ASD closure offers an excellent prognosis and prevents potentially life-threatening sequelae. Reporting such rare associations contributes to greater clinical awareness and may facilitate timely diagnosis and management in similar cases.

Conflict of interest: None declared