Background We describe a patient with an unusual cause of internal carotid artery occlusion resulting in a stroke.
Case Description A 41-year-old woman presented with a typical acute right middle cerebral artery territory infarct. Her hematological and cardiological status was assessed, including all extracranial vessels. Carotid angiography and a biopsy were performed of the occluded right internal carotid artery and demonstrated a myxoma. Cardiac investigations to determine the source of the myxoma, including transthoracic and transesophageal echocardiograms, CT and yo-yo CT scans, and MRI of the heart, were normal. No residual tumor or potential source of the tumor was found.
Conclusion The cause of stroke was a myxomatous occlusion of the right internal carotid artery. An entire cardiac tumor may have embolized with no detectable residual tumor in the heart; alternatively, a myxoma may have originated as a primary tumor in the carotid artery. To our knowledge, no primary myxoma has been reported to have originated in a blood vessel.
An atrial myxoma should be considered in young patients presenting without an obvious cause of a diffuse or focal neurological event because this is potentially treatable. We report a case of myxomatous occlusion of the right internal carotid artery in a young stroke patient with no radiological or clinical evidence of residual cardiac tumor or a source of the tumor.
A 41-year-old black woman presented with a bitemporal headache, loss of sensation of the left side of her face, and weakness of the left arm that had progressed over 12 hours to involve the left leg. There was no history of seizures, previous transient ischemic attacks, amaurosis fugax, or strokes. The only risk for a vascular event was hypertension, which was diagnosed on admission. She had no history of diabetes, hypercholesterolemia, gout, or cardiac disease. There was no family history of cerebrovascular disease or cardiac tumors. She did not smoke or consume alcohol. There was no history of oral contraceptive pill use.
Systemic inquiry revealed no symptoms of heart failure, chest pain, dyspnea, or syncope. Constitutional symptoms, such as fever, weight loss, fatigue, myalgia, and arthralgia, were absent.
On examination, blood pressure of the right arm was 170/80 mm Hg, and blood pressure of the left arm was 160/90 mm Hg. Neurological testing confirmed left-sided hemianesthesia and hemiplegia involving the face, arm, and leg. The higher functions were normal. Examination of the fundi and visual fields revealed no abnormalities. No abnormal movements or incoordination was observed. The pulse rate was 88 beats per minute, regular with all pulses present. There were no carotid bruits. There were no signs of other peripheral embolization, threatened limbs, retinal artery occlusion, peripheral vasculitis, or hematuria.
Examination of the patient's heart revealed the apex beat to be normal. The first and second heart sounds were normal with no extra sounds or murmurs. There was no evidence of congestive cardiac failure. The remainder of the general examination was normal.
Hematological investigation revealed a microcytic hypochromic iron deficiency anemia probably related to menorrhagia resulting from a multifibroid uterus. Erythrocyte sedimentation rate and C-reactive protein level were normal. Syphilis serology and retroviral status were negative. There was no evidence of a connective tissue disorder or coagulation abnormality. The fasting lipogram and glucose level were both normal. ECG and chest radiograph were normal. Carotid Doppler examinations revealed a right internal carotid artery occlusion distal to the bulb. There were no abnormal vessels on the left, although flow was noted to be turbulent.
A transthoracic echocardiogram (TTE) was normal. A transesophageal echocardiogram (TEE) showed no source of emboli, with normal heart chambers and left atrial appendage. Valves were normal without intracardiac masses being detected.
The right middle cerebral artery infarct was noted on CT. An arch aortogram with selective carotid artery injection revealed total occlusion of the right internal carotid artery 1 to 1.5 cm from its origin with no distal filling. All other vessels were normal with no evidence of aneurysms (Fig 1⇓).
A biopsy of the occluded right internal carotid artery was conducted. Surgery was conducted because of a study currently under way at our institution to determine the causes of carotid artery occlusion in young stroke patients (unpublished data). At surgery, it was technically impossible to shell out the entire tumor. An en bloc specimen of the carotid artery was excised with the bulk of the tumor being removed. Histology demonstrated the typical appearance of a myxoma with widely dispersed, small stellate cells in a myxomatous matrix occluding the lumen of the carotid artery. The myxoma was attached to the vessel wall but did not invade it. The vessel wall remained intact, demonstrating normal architecture with a preserved internal elastic lamina (Fig 2⇓).
After histopathological diagnosis, further investigations were carried out to exclude a residual cardiac tumor as the potential source of the myxoma. A repeat TTE showed the left atrium to be free of masses and residual tumor. All other heart chambers were normal. Another TEE was also interpreted as normal. A CT scan of the heart and a repeat yo-yo CT scan of the heart showed no abnormalities. MRI of the chest showed a completely normal heart with no masses or tumor stalk.
The patient improved slowly with rehabilitation and will be regularly followed with the use of echocardiography to exclude the possibility of recurring cardiac tumor. An MRI angiogram of the extracranial carotid circulation will evaluate any extension of the tumor.
The most common cardiac tumor associated with a neurological presentation is the atrial myxoma. This is an unusual but potentially treatable cause of stroke.1 2 The incidence of neurological complications in atrial myxomas is 25% to 45%.3 4
Patients with an atrial myxoma usually present with cardiac and constitutional complaints; neurological signs and symptoms are less common. Cardiac symptoms depend on the heart chamber that is involved and are predominantly the result of obstructive phenomena. Systemic manifestations include fever, malaise, arthralgias, weight loss, fatiguability, and anemia. The present patient had none of these, which emphasizes the unusual clinical presentation.
Embolic phenomena may result from myxomas arising from the left or right side of the heart. Right-sided tumors present with pulmonary emboli; left-sided tumors present with cerebrovascular events, threatened limbs, myocardial infarction, retinal artery occlusion, peripheral vasculitis, hypertension, or hematuria as a result of kidney emboli, all of which are caused by arterial occlusion.5 No embolic phenomena were clinically detected in our patient.
Rarely, as in our patient, neurological dysfunction may be the presenting feature, without a history of previous cardiac dysfunction and with normal cardiac auscultation.4 6 Often, the patient presents with repeated episodes of embolization before a diagnosis of atrial myxoma is made with histological examination.
The most common site for a cardiac myxoma is the left atrium (80%), attached to the atrial septum in the region of the fossa ovalis; 15% to 20% of myxomas occur in the right atrium, 4% occur in the ventricles,1 and 5% of patients have multiple myxomas.5 We could find no previous report of de novo benign myxomas occurring in the carotid arteries. Although a tumor source was not found in the heart of our patient despite extensive investigations, embolization of a myxoma remains a possibility because the intra-arterial tumor did not appear to be arising from or invading the vessel wall. However, aneurysms in the cerebral circulation resulting from direct invasion of vessel walls by embolized tumor tissue have been described.2 3 4
Microscopically, myxomas consist of an acid mucopolysaccharide myxoid matrix with single or nests of polygonal cells with scant cytoplasm. These cells, which are derived from multipotential mesenchymal cells, may form vascular channels (Fig 2⇑). Myxomas presenting as emboli are more likely to be irregular and extensively myxoid with minimal fibrosis, as seen in the present case. However, surface thrombosis was absent in our patient. In the present patient, we saw typical features of a myxoma. Other primary tumors that may occur at this site (eg, carotid body tumors) were excluded histologically.
Echocardiography is usually diagnostic of an atrial myxoma; TEE is nearly 100% sensitive.3 6 If the echocardiogram does not show the tumor,2 4 5 6 the diagnosis may then be confirmed with MRI, which will demonstrate the presence of tumor in virtually all cases.5
Despite repeated and thorough investigations, the present study did not demonstrate residual cardiac myxoma or the source of the tumor. The question remains of whether the entire cardiac tumor embolized or whether this represented a primary internal carotid artery myxoma.
Reprint requests to Dr N. Robbin, Neurology Unit, Area 455, Johannesburg Hospital, Private Bag X39, Johannesburg 2000, South Africa.
- Received August 23, 1996.
- Revision received October 24, 1996.
- Accepted November 8, 1996.
- Copyright © 1997 by American Heart Association
Knepper LE, Biller J, Adams HP Jr, Bruno A. Neurologic manifestations of atrial myxoma: a 12-year experience and review. Stroke. 1988;19:1435-1440.
Burke AP, Virmani R. Cardiac myxoma: a clinicopathologic study. Am J Cardiovasc Pathol. 1993;100:671-680.
Thompson J, Kapoor W, Wechsler LR. Multiple strokes due to atrial myxoma with a negative echocardiogram. Stroke. 1988;19:1570-1571.