From its large size, it may be assumed that the tumor was of long standing duration. Many patients with atrial myxoma experience a significant delay in diagnosis that can be attributed to the absence of symptoms, to misleading cardiac symptoms, or to the presence of extracardiac symptoms that fail to suggest the proper etiology.1
A recent study showed that the mean duration from the onset of neurologic symptoms to correct diagnosis was 36 months, and only 5.7% of patients with atrial myxoma had the proper diagnosis suggested clinically.8
It is, therefore, not surprising that this tumor was only discovered at autopsy in this patient.
When myxomas become more bulky, constitutional signs become more prominent, reflecting the tumor's obstructive presence. The most common symptom is dyspnea, which occurs in approximately 80% of patients with atrial myxoma. Nonspecific constitutional symptoms are reported in 10%–45% of patients. Not surprisingly, constitutional symptoms are reported most often in patients with left atrial myxoma, which occurs five times as often as its right atrial counterpart. Our patient serves as a reminder that such symptoms can also predominate with pathology on the right side of the heart. Right atrial myxomas may present with dyspnea, syncope, distension of neck veins, and other symptoms, which are related to tricuspid stenosis or frank interference with blood flow through the right heart. Our patient presented with both tachypnea and loss of consciousness. We suspect that these clinical symptoms and signs are the result of the obstruction to blood flow through the right heart by the tumor owing to its large size. This is further supported by the presence of hepatic steatosis in this patient. This obstruction may have significantly contributed to disease outcome in this patient as syncope and sudden death from complete obstruction of the tricuspid valve orifice are known to be the commonest causes of death in patients with right atrial myxomas.9,10
A temporal lobe bleed of the size seen in this patient cannot solely account for the sudden loss of consciousness and death within 6 h of presentation especially in the absence of any detectable abnormality in the brain stem.
Myxomas may also lead to multiple emboli in the cerebral circulation, depending on their location or other associated abnormalities, causing cerebral infarcts and hemorrhages. Formation of intracranial aneurysms, a less common phenomenon, may also be an associated event. Several possible mechanisms of aneurysm formation have been proposed.11
Indeed, some histopathologic studies have detected myxoma cells in the wall of aneurysms and others the interruption of the internal elastic lamina of cerebral arteries by invading tumor cells.10
Even though severe hypertension is a major cause of intracerebral hemorrhage in our environment, it is also possible that the hemorrhage in this patient could have resulted from an aneurysmal rupture following tumor migration from the right atrium through the ventricular septal defect into the systemic circulation – a form of paradoxical embolism. This association is extremely rare as extensive literature search did not yield any positive results. Interestingly, some authors have suggested that the hypertension found in patients with atrial myxoma may just be a stress response to the cerebral embolism as a result of the elaboration of pro-inflammatory cytokines and other mediators of paraneoplastic syndromes.12
Thus, the atrial myxoma in this patient may ultimately be linked to the intracerebral hemorrhage.
The diagnosis of atrial myxomas can be established by echocardiography, gated radionuclide blood-pool scan, or cardiac catheterization. Occasionally, the diagnosis is made by histologic examination of an embolus removed at operation.
Surgical excision is important for preventing obstruction of the tricuspid orifice, eliminating tumor emboli, maintaining systolic function, and restoring biventricular diastolic function.13
This gives excellent short- and long-term results especially with non-familial myxomas.14
Right atrial myxomas are rare and intracranial hemorrhage (in the context of a ventricular septal defect), syncope, and dyspnea are possible, though uncommon, initial clinical presentations. They should be considered in the differential diagnosis of cerebrovascular accidents.