Mitral Valve Mass Presenting as Recurrent Ischemic Strokes

Figure 1 : Bilateral ischemic infarcts on diffusion-weighted MRI. Acute ischemic infarcts can be seen involving the right thalamus, right occipital region and left posteroparietal region (solid white arrows). Gliosis consistent with known prior infarcts can also be visualized in the left thalamus and involving a large section of the left middle cerebral artery distribution (dashed white arrows).

This patient initially presented to our facility in 2009 at age 23 with right-sided weakness and aphasia. At that time, the patient was diagnosed with an acute ischemic infarct secondary to an occlusion of the anterior temporal branch of the left middle cerebral artery as identified on formal catheter angiogram. The patient was also noted to have two remote infarcts involving the left thalamus and right occipital region, of which the patient was unaware but had experienced referable symptoms without formal diagnosis. The patient had no known family history of stroke, vasculitis or cardiac pathology, and denied any personal medical history or use of tobacco/intravenous drugs. A full stroke work-up at the time of initial admission, including transthoracic echocardiogram, transesophageal echocardiogram, catheter angiography, CT angiography and a hypercoagulability workup failed to elucidate a clear etiology. Due to the strong suspicion of an underlying cardio embolic source, the patient was discharged on warfarin along with maximal standard medical therapy for secondary stroke prevention.

The patient was again admitted to the hospital 14 months after her initial presentation with new onset left-sided weakness and worsening aphasia. The patient was treated with intravenous tPA, which was halted upon return of the patient’s INR at 3.1. No adverse effects were noted secondary to administration of tPA in the context of the patient’s elevated INR. Her deficits resolved completely. Transthoracic echocardiogram revealed a mass on the mitral valve with mild mitral regurgitation; of note, there was no evidence of an intra cardiac mass on TTE six months prior to admission. Followup TEE visualized a 3.3 x 4.4 cm non-pedunculated mass on the atrial side of the posterior leaflet of the mitral valve consistent with a mitral fibroelastoma. The differential diagnosis for the mass included mitral valve myxoma, valvular lipoma, hematic cyst, Libman-Sacks endocarditis, maranteric endocarditis and subacute infective endocarditis. The patient was afebrile throughout her hospital admission and multiple blood cultures were negative. Repeat hypercoagulability workup, including ANA, was again negative. A chest/abdomen/pelvis computed tomography scan was negative for extra cardiac masses.

Given the patient’s presentation of recurrent ischemic stroke while supratherapeutic on coumadin, the patient was deemed to be at high risk for future ischemic insults and elected to undergo surgical removal of the mass. The operation revealed multi centric disease, with a larger 3x4 mm mass flanked by two smaller masses on the posterior leaflet of the mitral valve. Inspection of the anterior leaflet and atrial cavity revealed no further abnormalities. Histopathology of the samples was consistent with a diagnosis of mitral myxoma. Following the surgical resection of the mitral myxoma, the patient was taken off anticoagulation therapy and was followed with serial transthoracic echocardiograms which were negative for intra cardiac masses three years postoperatively.

Six months prior to the patient’s most recent admission, she presented to the emergency department with severe nausea and vomiting upon ingestion of food or medications. Per patient, her symptoms persisted for 2-3 months with only mild symptomatic relief from anti emetics. Retrospectively, the patient’s clinical presentation is concerning for possible chronic mesenteric ischemia secondary to subacute cardioembolic occlusion. Patient also endorsed intermittent palpitations for several months and had been referred for a Holter monitor and repeat echocardiography shortly before admission.

Following her current admission with a diagnosis of acute bilateral ischemic stroke, TTE revealed a mobile pedunculated 8x8 mm mass on the atrial aspect of the anterior mitral valve leaflet; diagnosis was confirmed with TEE (Figure 2). The patient was immediately placed on a heparin drip and was taken to surgery eight days after admission for excision of the suspected recurrent mitral valve myxoma. A 12 mm sessile mass was excised from the mid portion of the anterior leaflet. Intraoperative frozen section and follow-up permanent section returned as fibrinopurulent vegetation without evidence of myxoid stroma. Tissue bacterial culture was negative for aerobic and anaerobic organisms. Initial PAS and AFB stains were also negative; final cultures were pending at time of publication. The patient had no evidence of active infection throughout her hospital stay and blood cultures were negative. The patient’s anti-ß2 glycoprotein I IgG antibody level was found to be newly elevated at 54units/ ml from the single prior level of 13units/ml in 2009. The patient’s Russell viper venom test, anti-cardiolipin IgG/IgM/IgA antibodies and phosphatidylserine IgG/IgM/IgA antibodies were within normallimits.

Figure 2 : Visualization of intracardiac mass attached to atrial side of anterior leaflet of mitral valve. In panel a, a pedunculated 8x8 mm mass attached to the atrial aspect of The mitral valve can be visualized via transesophageal echocardiogram. The mass can be seen in cross-section on transthoracic echocardiogram in the parasternal short axis view (panel b).