Introduction

Cardiac myxoma is the most common primary benign cardiac tumor with an estimated annual incidence of 0.5 per million people. The tumors usually occur as sporadic lesions, but may occur as part of the rare Carney complex (cardiac and skin myxomas, lentiginosis, and endocrine abnormalities). Cardiac myxomas elicit a wide variety of symptoms in patients, such as heart failure, constitutional symptoms and embolic manifestation. Up to 50 % of the patients with myxomas present initially with stroke, while approximately one-third of the patients do not show any cardiac signs [1].

The formation of cerebral aneurysms is a very rare neurological complication of cardiac myxoma. In this report, we will describe a patient with multiple cerebral fusiform aneurysms 2 years after resection of cardiac myxoma and briefly review the previous literature.

Case report

A 60-year-old woman was admitted to our neurological department complaining of having a blunt headache that had lasted for 2 days. About 2 years ago, she was admitted to the cardiac surgery department because of chest distress. At that time, a Doppler echocardiography showed a parenchymatous mass with a clear boundary, which was derived from the inferior inter-atrial septum and had prolapsed into the left ventricle through the mitral valve during diastole. The patient underwent a thoracotomy with resection of the myxoma. The operation was successful without any complications. The post-operation follow-up showed the patient to be completely asymptomatic with no evidence of tumor recurrence or valvular vegetation with repeated echocardiographic examination. Since there was a lack of any neurological deficits,the patient did not receive any brain scanning thereafter.

For the present admission,her neurological examination was normal. Laboratory tests performed, including erythrocyte sedimentation rate, antistreptolysin O and C reactive protein, and leukocyte count, were all normal. A pre-contrast computerized tomography (CT) scan of the head indicated four intracranial mass-like lesions with moderate high density (two in the right sylvian fissure, one in the left sylvian fissure,and the last one in the anterior longitudinal fissure (Fig. 1a, d). MRI scans cannot be performed because of the implantation of a metal mechanical valve during the previous operation for the atrial myxoma. Since her primary physician suspected there may be metastatic brain lesions,she was referred for an F-18 FDG PET/CT scanning. PET (Fig. 1b, e) and PET/CT fusion images (Fig. 1c, f) demonstrated the hypometabolic feature of the four lesions shown previously in the CT image. An exploratory craniecotomy was performed on the lesion in the right sylvian fissure and a giant aneurysm was identified. The aneurysm was clipped after thrombus dislodgement and angioplasty. Histopathological examination of the tissue showed features of a massive intra-aneurysmal organized thrombus. The other three lesions were confirmed to be aneurysms by postoperative CTAngiogram (CTA) (Fig. 2).

Fig. 1
figure 1

CT scan images of brain. Four mass-like lesions with defined margin, round or oval in shape with homogeneously moderate high density were found in pre-contrast CT scan; two in right sylvian fissure, one in left sylvian fissure (a, black arrow),and one in the anterior longitudinal fissure (d, black arrow). F-18 FDG PET/CT scanning (b, e, black arrow) and PET/CT fusion images (c, f, black arrow) showed four lesions with hypometabolic features

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Fig. 2
figure 2

Postoperative CTA confirmed the other three lesions are fusiform aneurysms (white arrow)

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Discussion

Neurological manifestations of cardiac myxoma are usually encountered in three clinic-pathological scenarios: cerebral arterial embolism causing ischemia, neoplastic aneurysm formation with or without hemorrhage, and intraprenchymal myxomatous metastases. Acute cerebral embolism formation as a consequence of atrial myxomas has been well documented [2]. In contrast, the formation of multiple cerebral aneurysms is a very rare neurological complication. The exact incidence of myxoma-related intracranial aneurysms is still unknown. So far there are only approximately 50 cases being reported since the first case published in 1966 [3]. Aneurysm formation, as a secondary complication to atrial myxoma, is not caused by the changes of blood-flow dynamics but the invasion of myxomatous cells into the blood vessel. Thus, cerebral aneurysm associated with atrial myxoma has been described to have similar angiographic features to those caused by septic emboli, including peripheral location, multiplicity, and fusiform appearance [4, 5]. All these characteristics exactly matched what we have saw with this patient. The aneurysm was found in a craniotomy to be fusiform with an organized thrombus, which was consistent with the hypometabolic feature in the 18-FDP PET imaging. In this case, there was no evidence of infective endocarditis being detected after cardiac surgery,such as postoperative fever, leucocytosis, or signs of valvular vegetation in postoperative Doppler echocardiography. Thus, the diagnosis of the patient should be myxomatous aneurysms but not mycotic aneurysm associated with infective endocarditis.

Due to the limited published data of cerebral aneurysms derived from cardiac myxoma and the uncertainty of its natural history, no defined therapeutic guidelines of the disease have been issued. Although radiation therapy in combination with chemotherapy has been reported as an effective method for the degradation of myxoma metastasis, its efficacy in pre-formed aneurysms remains unknown. In this case, of the four total masses, only the lesion in the right sylvian fissure was surgically removed. Because of the multiplicity and fusiform nature of the aneurysms, the other three aneurysms were difficult to be clipped or coiled. Therefore, no treatment was performed on them and the patient will be closely followed up for future treatment.

Our report has presented an extremely rare imaging characteristic of multiple myxomatous aneurysms in F-18 FDG PET scan. Although the image might not be critical for the diagnosis of intra-cranial aneurysms, PET-CT is often a useful tool in the differential diagnosis of intra-cranial lesions. This case suggests that patients with multiple intra-cranial lesions, with or without a history of atrial myxoma or cardiac signs, should be considered as having myxomatous aneurysm or other related neurological complications.