Abstract
Blood cysts in the heart are often incidentally found during post-mortem examinations in infants, and usually do not cause clinical symptoms. They almost always regress spontaneously, and only a few cases of embolization or valvular dysfunction have been reported previously.
We report a 62-year-old man who presented with chest discomfort and dyspnea on exertion for several years, and was found to have a dynamic murmur in left ventricular outflow tract (LVOT) on physical examination. His echocardiogram demonstrated two large blood cysts attached to the subvalvular apparatus of mitral valve, causing significant LVOT obstruction and mild to moderate mitral regurgitation. The cysts were surgically excised and pathology confirmed simple blood cysts.
<Learning objective: To the best of our knowledge, this is the first reported case of twin blood cysts with severe left ventricular outflow tract obstruction in an adult, since most of these cysts either regress spontaneously in childhood or remain asymptomatic in adults.>
Keywords: Blood cyst, Left ventricle outflow obstruction, Cardiac surgery, Transthoracic echocardiography, Transesophageal echocardiography
Introduction
Small blood-filled cysts of the heart valves are often found at post-mortem examinations in infants and often have little clinical significance [1]. Detection of larger cysts in adults is very rare since most of these cysts regress spontaneously. Although acquired blood cysts have been reported, a congenital origin has been described in most cases [2]. Most often, blood cysts are attached to cardiac valves or their supporting structures [3]. While these cysts are often asymptomatic, a few cases of embolization or valvular dysfunction have been reported. Because of their typically benign nature, surgical resection should be reserved for those cystic masses that interfere with normal cardiac function. Here, we report a case with two large blood cysts, attached to the subvalvular apparatus of anterior mitral valve leaflet (AMVL), causing significant left ventricular outflow tract (LVOT) obstruction and mild to moderate mitral regurgitation (MR).
Case report
A 62-year-old man was referred to our hospital for evaluation of chest discomfort and dyspnea on exertion present for several years, with a recent increase in severity. His past medical history included a cerebrovascular accident 20 years previously with mild left side hemiparesia. On admission, his vital signs were stable; on physical examination a dynamic murmur in LVOT was audible which increased with Valsalva maneuver. Electrocardiogram showed atrial fibrillation without any significant ST segment and T wave changes. Chest radiography showed normal heart size with no other abnormality. Transthoracic echocardiogram showed two large cystic masses (21 mm × 21 mm and 19 mm × 8 mm) in the left ventricle, attached to the posteromedial papillary muscle and chordae tendineae, which protruded into LVOT during systole, causing significant obstruction and gradient (Peak pressure gradient = 70 mmHg) (Fig. 1A, B).
Fig. 1.
Transthoracic echocardiography apical five-chamber view showed severe left ventricular outflow tract obstruction and increased gradient (Mean pressure gradient = 37 mmHg, peak pressure gradient = 77 mmHg) (A). Transthoracic apical four-chamber view showed two adherent round cystic masses and their size in the left ventricle that seemed to be very close to the tip of the anterior mitral valve leaflet (B).
Transesophageal echocardiogram (TEE) confirmed the presence of two mobile round cystic masses, adherent to each other with hyperechogenic walls and hypoechogenic content, which were attached to the chordate structure of posteromedial papillary muscle and tip of AMVL (only 3 mm distance between the cyst and tip of AMVL) causing mild to moderate MR. Protrusion into LVOT during systole and LVOT obstruction was confirmed on TEE (Video 1A, B in Supplementary material).
Thoracic computed tomography excluded the possibility of hydatid cyst as the origin of the cysts. Because of the clinical symptoms and interference with valve function on imaging, the heart team planned surgical resection of the cysts. Given the patient’s age and symptoms, preoperative coronary angiography was performed to evaluate coronary disease, which showed moderate lesion in middle part of left anterior descending coronary artery without significant obstruction.
During the cardiac surgery, cysts were found to be attached firmly to several chorda, and therefore mitral valve replacement was unavoidable. The cysts were inadvertently ruptured during surgical resection and their content was discharged (Fig. 2A, B). They were filled with old and brownish fluid with yellowish and translucent walls.
Fig. 2.
Surgical and histologic findings. (A) The cysts were attached to the chordeal structure of mitral valve and very close (3 mm) to the tip of anterior mitral valve leaflet. (B) Excised blood cyst. The cysts were filled with old and brownish fluid and the cysts wall were yellowish and translucent. (C, D) Hematoxylin and eosin stained sections disclosed the unilocular cyst wall composed of a loose connective fibrous tissue lined by a single layer of flattened endothelium.
The patient had an uneventful recovery from the operation, and has been maintained on lifelong anticoagulation. He has had no recurrence of symptoms, and repeat echocardiography showed well seated and normal functioning prosthetic mitral valve without LVOT obstruction and no residue of the cysts.
Pathology
Macroscopic examination showed previously opened cysts, 2.5 × 2 cm in aggregate. The cyst wall was translucent, 1 mm in thickness, and inner and outer surfaces were smooth with no septation. Light microscopic examination of paraffin-embedded sections of samples revealed cyst wall attached to portions of valvular tissue. The unilocular cyst wall comprised loose connective tissue lined by a single layer of flattened endothelium, consistent with blood cyst. The removed valve tissue showed mild fibrotic changes (Fig. 2C, D).
Discussion
Intracardiac blood cysts are usually asymptomatic, small, and have congenital origin [2]. They often disappear with age [1], making the detection of such cysts in the elderly a rare finding. When persisting, they can reach large sizes and cause valvular dysfunction [4]. The most common location is atrioventricular valves [5].
Several hypotheses have been proposed to explain the pathophysiology and development of such cysts. They include blood cyst formation during development of the valves as a result of passing and trapping blood in crevices that are later sealed, or hematoma formation in subvalvular region secondary to the occlusion of small vascular branches of end-arteritis. All other hypotheses suggest congenital origin of these simple blood cysts, and on rare occasion, blood cysts were reported to be due to hematoma formation in a patient with a previous history of cardiac surgery, even though there is no known causal association between cyst development and previous cardiac surgery [6]. Overall, there is no consensus about the mechanism of blood cyst formation, or the optimal management of asymptomatic blood cysts. However, it seems reasonable to conservatively manage asymptomatic cases [2], [4], reserving surgical resection for symptomatic patients, or those who require an open cardiac surgery for other reasons [1].
Here we presented a case of two symptomatic large blood cysts in a patient without any prior history of cardiac surgery. The blood cysts interfered with normal valvular function, causing severe LVOT obstruction leading to symptoms of chest discomfort and dyspnea in the patient. Therefore, the cysts were surgically resected. The question that was left unanswered in this patient is whether there was a relationship between these cysts and his cerebrovascular accident many years ago, or if his untreated atrial fibrillation resulted in stroke.
Conflict of interest
The authors declare no conflict of interest.
Footnotes
Supplementary data associated with this article can be found, in the online version, at https://doi.org/10.1016/j.jccase.2018.05.004.
Appendix A. Supplementary data
The following are Supplementary data to this article:
Transesophageal imaging in midesophageal long-axis view revealed the existence of two mobile round cystic masses, adherent to each other with hyperechogenic walls and hypoechogenic content that was attached to the chordate structure of posteromedial papillary muscle and the tip of anterior mitral valve leaflet (A). Color turbulence in the left ventricular outflow tract (LVOT) showed LVOT narrowing and obstruction due to the protruding of the cysts to LVOT during systole (B).
Transthoracic echocardiography apical four-chamber view showed two adherent round cystic masses in the left ventricle that seemed to be attached to the chordae of anterior mitral valve leaflet.
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Associated Data
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Supplementary Materials
Transesophageal imaging in midesophageal long-axis view revealed the existence of two mobile round cystic masses, adherent to each other with hyperechogenic walls and hypoechogenic content that was attached to the chordate structure of posteromedial papillary muscle and the tip of anterior mitral valve leaflet (A). Color turbulence in the left ventricular outflow tract (LVOT) showed LVOT narrowing and obstruction due to the protruding of the cysts to LVOT during systole (B).
Transthoracic echocardiography apical four-chamber view showed two adherent round cystic masses in the left ventricle that seemed to be attached to the chordae of anterior mitral valve leaflet.