Myxoma is a rare primary cardiac tumor frequently localized in the left atrium appended to the inter-atrial septum, the right atrial localization represents 15–25% [2, 7, 12].
It occurs more predominantly in women than in men with a sex ratio of 2 to 3 women to 1 man. The annual incidence is estimated at 0.5 per 1 million people with a peak occurring in young adults aged 30 to 60 years [3, 4, 10]. It represents 21.5–80% of all cardiac tumors according to the series and 75% of these tumors are located in the left atrium (LA) [1–4]. The case we report is a 46-year-old woman with no family history, which is consistent with the data in the literature. The sporadic form is mostly predominant. In about 7% of cases, we can observe familial forms with an autosomal dominant transmission, the typical example is the Carney complex associating cutaneous and cardiac myxoma, skin lesions, endocrinopathies, and non-myxomatous extracardiac tumors [1, 11, 12].
The clinical presentation of left atrium myxomas varies depending on its location, size, and mobility [3, 11, 21]. Thus, non-specific systemic symptoms such as asthenia, myalgia, arthralgia, fever, and weight loss; due to the expression of interleukin 6 by myxoma may be the first revelations of this cardiac tumor [1, 3, 5]. These constitutional, general symptoms can err the diagnosis and lead to a delay in diagnosis or the revelation of the disease by a more serious manifestation such as cerebral embolic events or elsewhere in the vascular tree [16, 21, 27]. These embolic incidents are found in 30 to 40% of cases and were the revealing mode in the first description of the left atrium myxoma described by Goldberg et al in a hemiparesis patient, similar to our patient [1, 16, 17]. These accidents are caused by the embolization of a myxomatous aneurysm, a friable tumor fragment, or an adherent thrombus, which explains why anticoagulation not only protects from these embolization incidents but also decreases the risk of dementia by progressive infarction or death by massive embolism in addition to neurological functional sequelae [1, 4, 19]. Ischemic strokes associated with myxoma of the left atrium have been described even in the pediatric population, but represent only 0.5% of all strokes. The third group of symptoms that make up the triad is related to the obstruction of the mitral valve by myxoma, which leads to dyspnea, dizziness, or even syncope or sudden death [2, 3, 4, 23].
Transthoracic echocardiography (TTE) is the non-invasive imaging modality of choice, to be performed in patients with a stroke in order to eliminate the cardioembolic origin [1, 8, 13, 37]. In the case of a myxoma, TTE shows an inhomogeneous mass, pediculated, appended to the interatrial septum, and usually located in the left atrium [4, 5, 13, 17]. This was the TTE finding of our young patient in whom a TTE was performed as part of the etiological assessment of her ischemic stroke. TTE may show no signs in 36% of cases and transesophageal echocardiography is a good option for a better and more accurate description of the tumor, its location, and attachment with a sensitivity close to 100% [6, 15]. MRI and/or cardiac CT scan can help in the tissue characterization of the mass, its exact location, and cardiac anatomy and therefore valuable support for the surgical approach [1, 4].
Once diagnosed, management of cardiac myxoma should be early and complete to avoid serious complications such as an ischemic stroke, amnesia, myocardial infarction, syncope, sudden death, and possible fatal relapse [8, 19]. Surgery is the treatment of choice for the complete removal of the tumor [14, 18].
Histological analysis of the removed tumor is the gold standard to confirm the diagnosis by highlighting a myxoid proliferation of cells expressing calretinin in immunohistochemistry. Cardiac myxoma is a histologically benign tumor resulting from the proliferation of multipotent mesenchymal cells of the oval fossa [9, 23, 37], it presents a risk of recurrence of 1 to 5% after inadequate surgical excision. Recurrence occurs for poorly differentiated active myxomas [3, 4].