Blood Cyst of the Mitral Valve: Detection by Transthoracic and Transesophageal Echocardiography Song Wei Xie, MD, On-Lun Lu, MD, and Michael H. Picard, MD, Shanghai, China, and Boston, Massachusetts
Two-dimensional transthoracic and transesophageal echocardiography have become important modalities in the evaluation of the mechanism of symptomatic mitral regurgitation. We report the use of echocardiography in the detection of an unusual cause of mitral regurgitation, that of multiple large blood cysts involving the posterior leaflet of the mitral valve. (JAM Sac ECHOCARDIOGR 1992;5:547-50.)
Although small blood-filled cysts of the cardiac valves are found in infants at necropsy as an incidental finding, the occurrence of such cysts in children and adults is rare. 1 When present in adults, the cysts are usually small and inconsequential findings. Rarely, large cysts c·an be present with symptoms of valvular obstruction or regurgitation. 2 -4 Because of the location and morphologic characteristics of cysts, echocardiography is an ideal modality for diagnosis. In this case study, we report the first observations of transesophageal echocardiography of blood cyst of the mitral valve.
CASE REPORT
A 41-year-old Chinese woman sought medical attention after several months of new and progressive dyspnea on minimal exertion. Before these symptoms, she had been in excellent health with normal exercise tolerance. She had no history of endocarditis, collagen vascular disease, or rheumatic fever. Physical examination revealed a well-developed, well-nourished woman. Vital signs were normal and there was no evidence of cyanosis. On cardiac examination the palpable maximum impulse was normal and in the midclavicular line. The first heart sound was diminFrom the Division of Cardiology, Shanghai Chest Hospital, the Department of Pathology, Shanghai Second Medical University, the Cardiac Unit of the Massachusetts General Hospital, and Harvard Medical School. Reprint requests: Michael H. Picard, MD, Cardiac Ultrasound Laboratory, Founders House 8, Massachusetts General Hospital, Boston, MA 02114. 27/l/38724
ished in intensity and the second sound was normal. A 2 I 6 holosystolic murmur was heard over apex without radiation or thrill. Electrocardiogram and chest x-ray film were unremarkable. Mter echocardiography, a digital subtraction angiogram was performed with injection into the left upper pulmonary vein from a catheter placed across a patent foramen ovale. An abnormal round filling defect was noted on the posterior mitral leaflet. Echocardiographic Findings
Transthoracic two-dimensional echocardiography revealed a normal-sized heart. One cystic mass was attached to the posterior leaflet of the mitral valve along the atrial surface. A mitral regurgitation signal was detected by pulsed wave Doppler to the midportion of the left atrium. Transesophageal echocardiogram was performed to more completely assess the nature and position of the mass. On this examination two cysts, measuring 1.3 x 1 cm and 0.2 X 0.3 cm, respectively, were observed fixed to the atrial side of the posterior leaflet (Figure 1). There was no obstruction of the mitral orifice during diastole. In systole, the body and tip of the posterior leaflet prolapsed into the left atrium, causing an anteriorally directed jet of mitral regurgitation of moderate severity. In systole the larger cyst appeared to increase in size slightly compared with its diastolic dimensions. Operative Findings
At surgery the left atrium was exposed through a right atriotomy. Two soft masses were found attached to the atrial surface of the posterior mitral valve leaflet. One measured 1.5 x 1.5 x 1 cm and 547
548
Journal of the American Society of Echocardiography
Xie et al.
Figure 1 Systolic and diastolic images from ttansesophageal echocardiogram displaying one large (C) and one small (arrow) blood cyst associated with the left atrial surface of the posterior leaflet of the mitral valve. The images are modified five-chamber views with reversal of right and left. LA> Left atrium; LV, left ventricle; RV) right ventricle.
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Figure 2 Low-power micrograph of blood cyst. The wall is composed of dense connective tissue (CT) with endothelial cells lining both the inner (EN) and outer (EX) surfaces.
was attached to the leaflet by a broad base. This was resected. The other lesion, measuring 0.3 x 0.2 x 0.2 ,n, was not resected. After resection the valve appeared competent without prolapse or chordal disruption, and the patient's postoperative course was unremarkable. Although mitral leaflet coaptation ap-
peared normal on subsequent transthoracic echocardiograms, mild mitral regurgitation was detected by calor flow Doppler. The patient's presenting symptoms have resolved. Histopathologic examination of the resected mass revealed a thin-walled blood-filled cyst composed pri-
Volwne 5 Nwnber 5 September-October 1992
Detection of blood cyst by echocardiography 549
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Figure 3 Higher power magnification of the cyst again demonstrating the homogeneous composition of the cyst walls. Connective tissue; EN, inner surface; EX, outer surface.
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marily of fibrous connective tissue and lined with endothelium (Figures 2 and 3) . There was no evidence of inflammation, infection, or infiltration. DISCUSSION
Although small blood cysts measuring less than l mm involving the cardiac valves have been observed in up to 56% of autopsy specimens of neonates and infants, their occurrence in children and adults is rare. 1 Because of their size, they are often mistaken for an adherent thrombus. Large blood cysts measuring up to 3 cm in diameter are rare in adults but have been detected and reported when associated with symptoms of valvular stenosis or, as is this case, valvular regurgitation. 2 •4 · 7 When the cysts are associated with the mitral subvalvular apparatus, symptomatic left ventricular outflow tract obstruction can arise. 7 The rarity of blood cysts is demonstrated by the fact that detection by two-dimensional transthoracic echocardiography has only been reported twice. 6 •7 Several hypotheses have been advanced to explain the development of blood cysts. The two most popular are that (l) the cysts are formed during valve development by blood trapped within cusp crevices which subsequently seal off, 8 and (2) the cysts are
the result of dilatation of normal invaginations of valve cusps. 9 This case illustrates the value of ultrasound in the differential diagnosis of this lesion. Whereas the contrast angiogram only provided a silhouette of the mass associated with the valve leaflet, the echocardiogram revealed the cystic nature of the lesion and immediately helped reduce the differential diagnosis from one including all mass lesions (vegetation, tumar, and thrombus) to a more concise list including blood cyst, echinococcal cyst, and mitral valve aneurysm. Transesophageal echocardiography was the only imaging modality that correctly identified the second small cyst. Additionally, on the transesopheal echocardiogram, the cystic lesions could be distinctly differentiated from the valve leaflet and thus were not confused with the echocardiographic appearance of a mitral valve aneurysm. Mitral valve aneurysms, as sequelae from infective endocarditis, differ from the lesion observed in this case in several respects. They usually involve the anterior leaflet, typically a discontinuity in the leaflet is visualized, and the mitral regurgitation can often be observed to originate through the perforation. In our case, in contrast, the posterior leaflet was involved, the lesions were distinct from the valve, and the lesions did not cause a discrete interruption in the leaflet.
Journal of the American Society of Echocardiography
550 Xie et al.
In this case the transesophageal echocardiogram provided a precise quantification and localization of the blood cysts, which aided in planning the surgical procedure and sparing of the native mitral valve. REFERENCES l. Begg JG. Blood filled cysts in the cardiac valve cusps in foetal
life and infancy. Journal of Pathology and Bacteriology 1964;87:177-8. 2. Sakakibara S, Katsuhara K, Iida Y, Nishida H. Pulmonary subvalvular turnor. Diseases of the Chest 1967;51:637-41. 3. Bliddal J, Christensen N, Efsen F. Intracardial blood cyst causing subpulrnonary stenosis in congenitally corrected transposition. European Journal of Cardiology 1977;5:17-27.
4. Gallucci V, Stritoni P, Fasoli G, Thiene G. Giant blood cyst of tricuspid valve: successful excision in an infant. Br Heart J 1976;38:990-2. 5. Leatherman L, Leachman RD, Hallman GL, Cooley DA. Cyst of the mitral valve. Am J Cardiol 1968;21:428-30. 6. Hauser AM, Rathod K, McGill J, Rosenberg BF, Gordon S, Timmis GC. Blood cyst of the papillary muscle: clinical, echocardiographic and anatomic observations. Am J Cardiol 1983;51 :612-3. 7. Arnold IR, Huhner PJB, Firmin RK. Blood filled cyst of the papillary muscle of the mitral valve producing severe left ventricular outflow tract obstruction. Br Heart J 1990;63:132-3. 8. Boyd TAB. Blood cysts on the heart valves of infants. Am J Pathol 1949;25:757-9. 9. Levinson SA, Learner A. Blood cysts on the heart valves of newborn infants. Archives of Pathology 1932;14:810-7.
Correction In the article by Gardin et al. entitled "Echocardiographic design of a multicenter investigation of free-living elderly subjects: the cardiovascular health study'' (J AM Soc EECHOCARDIOGR 1992;5:63-72), the formula on page 68 for determining left ventricular wall stress (LVESS) was incorrectly printed. The correct formula is as follows: LVESS =
0.334 P x (LVIDs) PWTs x [1+(PWTs/LVIDs)]
where P is the systolic arm-cuff pressure, PWTs is the left ventricular posterior wall thickness in systole, and LVIDs is the left ventricular dimension in systole.
Two-dimensional transthoracic and transesophageal echocardiography have become important modalities in the evaluation of the mechanism of symptomatic mitral regurgitation. We report the use of echocardiography in the detection of an unusual cause of mitral regurgitation, that of multiple large blood cysts involving the posterior leaflet of the mitral valve. (JAM Sac ECHOCARDIOGR 1992;5:547-50.)
Although small blood-filled cysts of the cardiac valves are found in infants at necropsy as an incidental finding, the occurrence of such cysts in children and adults is rare. 1 When present in adults, the cysts are usually small and inconsequential findings. Rarely, large cysts c·an be present with symptoms of valvular obstruction or regurgitation. 2 -4 Because of the location and morphologic characteristics of cysts, echocardiography is an ideal modality for diagnosis. In this case study, we report the first observations of transesophageal echocardiography of blood cyst of the mitral valve.
CASE REPORT
A 41-year-old Chinese woman sought medical attention after several months of new and progressive dyspnea on minimal exertion. Before these symptoms, she had been in excellent health with normal exercise tolerance. She had no history of endocarditis, collagen vascular disease, or rheumatic fever. Physical examination revealed a well-developed, well-nourished woman. Vital signs were normal and there was no evidence of cyanosis. On cardiac examination the palpable maximum impulse was normal and in the midclavicular line. The first heart sound was diminFrom the Division of Cardiology, Shanghai Chest Hospital, the Department of Pathology, Shanghai Second Medical University, the Cardiac Unit of the Massachusetts General Hospital, and Harvard Medical School. Reprint requests: Michael H. Picard, MD, Cardiac Ultrasound Laboratory, Founders House 8, Massachusetts General Hospital, Boston, MA 02114. 27/l/38724
ished in intensity and the second sound was normal. A 2 I 6 holosystolic murmur was heard over apex without radiation or thrill. Electrocardiogram and chest x-ray film were unremarkable. Mter echocardiography, a digital subtraction angiogram was performed with injection into the left upper pulmonary vein from a catheter placed across a patent foramen ovale. An abnormal round filling defect was noted on the posterior mitral leaflet. Echocardiographic Findings
Transthoracic two-dimensional echocardiography revealed a normal-sized heart. One cystic mass was attached to the posterior leaflet of the mitral valve along the atrial surface. A mitral regurgitation signal was detected by pulsed wave Doppler to the midportion of the left atrium. Transesophageal echocardiogram was performed to more completely assess the nature and position of the mass. On this examination two cysts, measuring 1.3 x 1 cm and 0.2 X 0.3 cm, respectively, were observed fixed to the atrial side of the posterior leaflet (Figure 1). There was no obstruction of the mitral orifice during diastole. In systole, the body and tip of the posterior leaflet prolapsed into the left atrium, causing an anteriorally directed jet of mitral regurgitation of moderate severity. In systole the larger cyst appeared to increase in size slightly compared with its diastolic dimensions. Operative Findings
At surgery the left atrium was exposed through a right atriotomy. Two soft masses were found attached to the atrial surface of the posterior mitral valve leaflet. One measured 1.5 x 1.5 x 1 cm and 547
548
Journal of the American Society of Echocardiography
Xie et al.
Figure 1 Systolic and diastolic images from ttansesophageal echocardiogram displaying one large (C) and one small (arrow) blood cyst associated with the left atrial surface of the posterior leaflet of the mitral valve. The images are modified five-chamber views with reversal of right and left. LA> Left atrium; LV, left ventricle; RV) right ventricle.
J
EX
CT
EN
/
•
Figure 2 Low-power micrograph of blood cyst. The wall is composed of dense connective tissue (CT) with endothelial cells lining both the inner (EN) and outer (EX) surfaces.
was attached to the leaflet by a broad base. This was resected. The other lesion, measuring 0.3 x 0.2 x 0.2 ,n, was not resected. After resection the valve appeared competent without prolapse or chordal disruption, and the patient's postoperative course was unremarkable. Although mitral leaflet coaptation ap-
peared normal on subsequent transthoracic echocardiograms, mild mitral regurgitation was detected by calor flow Doppler. The patient's presenting symptoms have resolved. Histopathologic examination of the resected mass revealed a thin-walled blood-filled cyst composed pri-
Volwne 5 Nwnber 5 September-October 1992
Detection of blood cyst by echocardiography 549
EX
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Figure 3 Higher power magnification of the cyst again demonstrating the homogeneous composition of the cyst walls. Connective tissue; EN, inner surface; EX, outer surface.
er,
marily of fibrous connective tissue and lined with endothelium (Figures 2 and 3) . There was no evidence of inflammation, infection, or infiltration. DISCUSSION
Although small blood cysts measuring less than l mm involving the cardiac valves have been observed in up to 56% of autopsy specimens of neonates and infants, their occurrence in children and adults is rare. 1 Because of their size, they are often mistaken for an adherent thrombus. Large blood cysts measuring up to 3 cm in diameter are rare in adults but have been detected and reported when associated with symptoms of valvular stenosis or, as is this case, valvular regurgitation. 2 •4 · 7 When the cysts are associated with the mitral subvalvular apparatus, symptomatic left ventricular outflow tract obstruction can arise. 7 The rarity of blood cysts is demonstrated by the fact that detection by two-dimensional transthoracic echocardiography has only been reported twice. 6 •7 Several hypotheses have been advanced to explain the development of blood cysts. The two most popular are that (l) the cysts are formed during valve development by blood trapped within cusp crevices which subsequently seal off, 8 and (2) the cysts are
the result of dilatation of normal invaginations of valve cusps. 9 This case illustrates the value of ultrasound in the differential diagnosis of this lesion. Whereas the contrast angiogram only provided a silhouette of the mass associated with the valve leaflet, the echocardiogram revealed the cystic nature of the lesion and immediately helped reduce the differential diagnosis from one including all mass lesions (vegetation, tumar, and thrombus) to a more concise list including blood cyst, echinococcal cyst, and mitral valve aneurysm. Transesophageal echocardiography was the only imaging modality that correctly identified the second small cyst. Additionally, on the transesopheal echocardiogram, the cystic lesions could be distinctly differentiated from the valve leaflet and thus were not confused with the echocardiographic appearance of a mitral valve aneurysm. Mitral valve aneurysms, as sequelae from infective endocarditis, differ from the lesion observed in this case in several respects. They usually involve the anterior leaflet, typically a discontinuity in the leaflet is visualized, and the mitral regurgitation can often be observed to originate through the perforation. In our case, in contrast, the posterior leaflet was involved, the lesions were distinct from the valve, and the lesions did not cause a discrete interruption in the leaflet.
Journal of the American Society of Echocardiography
550 Xie et al.
In this case the transesophageal echocardiogram provided a precise quantification and localization of the blood cysts, which aided in planning the surgical procedure and sparing of the native mitral valve. REFERENCES l. Begg JG. Blood filled cysts in the cardiac valve cusps in foetal
life and infancy. Journal of Pathology and Bacteriology 1964;87:177-8. 2. Sakakibara S, Katsuhara K, Iida Y, Nishida H. Pulmonary subvalvular turnor. Diseases of the Chest 1967;51:637-41. 3. Bliddal J, Christensen N, Efsen F. Intracardial blood cyst causing subpulrnonary stenosis in congenitally corrected transposition. European Journal of Cardiology 1977;5:17-27.
4. Gallucci V, Stritoni P, Fasoli G, Thiene G. Giant blood cyst of tricuspid valve: successful excision in an infant. Br Heart J 1976;38:990-2. 5. Leatherman L, Leachman RD, Hallman GL, Cooley DA. Cyst of the mitral valve. Am J Cardiol 1968;21:428-30. 6. Hauser AM, Rathod K, McGill J, Rosenberg BF, Gordon S, Timmis GC. Blood cyst of the papillary muscle: clinical, echocardiographic and anatomic observations. Am J Cardiol 1983;51 :612-3. 7. Arnold IR, Huhner PJB, Firmin RK. Blood filled cyst of the papillary muscle of the mitral valve producing severe left ventricular outflow tract obstruction. Br Heart J 1990;63:132-3. 8. Boyd TAB. Blood cysts on the heart valves of infants. Am J Pathol 1949;25:757-9. 9. Levinson SA, Learner A. Blood cysts on the heart valves of newborn infants. Archives of Pathology 1932;14:810-7.
Correction In the article by Gardin et al. entitled "Echocardiographic design of a multicenter investigation of free-living elderly subjects: the cardiovascular health study'' (J AM Soc EECHOCARDIOGR 1992;5:63-72), the formula on page 68 for determining left ventricular wall stress (LVESS) was incorrectly printed. The correct formula is as follows: LVESS =
0.334 P x (LVIDs) PWTs x [1+(PWTs/LVIDs)]
where P is the systolic arm-cuff pressure, PWTs is the left ventricular posterior wall thickness in systole, and LVIDs is the left ventricular dimension in systole.
