Cardiac Myxoma Originating from the Anterior Mitral Leaflet. Case Reports

Transcription

1 Case Reports Cardiac Myxoma Originating from the Anterior Mitral Leaflet Michael Yu-Chih CHEN, 1 MD, Ji-Hung WANG, 1 MD, Shen-Feng CHAO, 2 MD, Yung-Hsiang HSU, 3 MD, Da-Chung WU, 1 MD, and Cha-Po LAI, 1 MD SUMMARY Cardiac myxoma arising from the anterior mitral leaflet is extremely rare. A 47-yearold Taiwanese male was found to have a cm myxoma originating from the atrial side of the anterior mitral leaflet using transesophageal echocardiography. The tumor was successfully treated by surgical excision. The resected tumor was a well-defined encapsulated mass with a broad-base stalk arising from the anterior mitral leaflet. To detect the early recurrence, a semiannual follow-up examination using transesophageal echocardiography is needed. (Jpn Heart J 2003; 44: ) Key words: Cardiac tumor, Mitral valve, Transesophageal echocardiography PRIMARY cardiac tumors are uncommon and their autopsy incidence has been calculated to be between % and 0.33%. About 50% of these tumors are myxoma which usually arise from the interatrial septum. 1) We report here an extremely rare case of myxoma originating from the anterior mitral leaflet, which was diagnosed and located using transesophageal echocardiography (TEE). CASE REPORT A 47-year-old male Taiwanese patient was referred to our hospital for the evaluation of intermittent attacks of shortness of breath and palpitations. These symptoms had appeared 1 year previously and were not associated with physical activity, while the severity and frequency of these symptoms worsened in the previous 3 months. His height was 170 cm, body weight 68 kg, blood pressure 114/80 mmhg, pulse rate 90 beats per minute without deficit, respiratory rate 22 per minute, and body temperature 36.2 C. Auscultation revealed a pan-systolic murmur (II/VI) at the apex, a rumble murmur in diastolic phase, and moist rales heard in the inspira- From the 1 Departments of Cardiology, 2 Cardiovascular Surgery, and 3 Pathology, Tzu-Chi Buddhist General Hospital, Hualien, Taiwan. Address for correspondence: Cha-Po Lai, MD, Tzu-Chi Buddhist General Hospital, 707 Sec. 3, Chung-Yan Rd., Hualien, Taiwan. Received for publication July 18, Revised and accepted September 19,

2 430 CHEN, ET AL Jpn Heart J May 2003 tory phase. No abnormal neurological symptoms or signs were found. Chest radiography showed cardiomegaly with bilateral lung congestion (Figure 1). Blood biochemistry revealed normal serological findings for liver and kidney function. Transthoracic echocardiography (TTE) revealed a normal range for left ventricular function (end diastolic diameter/end systolic diameter = 45/26 mm, ejection fraction = 74%) and wall thickness (interventricular septum/posterior wall = 11/7 mm), while the left atrium was distended (50 mm) and contained a mobile mass. Doppler echocardiography showed moderate mitral and tricuspid regurgitation. The calculated pressure gradient through the tricuspid valve was 78 mmhg, which suggested an elevated pulmonary artery pressure. TEE was then performed the next day. There was a heterogeneous mass (5 3.7 cm) adhering to the atrial side of the anterior mitral leaflet which prolapsed into the left ventricle during the diastolic phase (Figure 2-A). Cardiac myxoma arising from the Figure 1. Chest radiography shows the cardiomegaly and bilateral lung congestion.

3 Vol 44 No 3 MITRAL VALVE MYXOMA 431 anterior mitral leaflet was suspected. During the operation, a well-defined encapsulated gelatinous mass (5 4 3 cm) with a broad-base stalk arising from the anterior mitral leaflet was found after a median sternotomy and opening of the left atrium. This mass with a part of the leaflet around the tumor was resected and the mitral valve was repaired with a direct suture. On gross section, this mass was myxoid with a focal hemorrhage and cystic changes (Figure 2-B). Microscopically, the lesion consisted of spindle- Figure 2. A: Transesophageal echocardiogram shows a heterogeneous mass adhered to the atrial side of the anterior mitral leaflet. B: Macroscopically, the resected tumor is a well-defined encapsulated gelatinous mass with a broad-base stalk attached to the anterior mitral leaflet (arrow). LV left ventricle; RV right ventricle.

4 432 CHEN, ET AL Jpn Heart J May 2003 shaped and stellate cells in a capillary-rich myxoid stroma with a lymphocytic infiltrate and a marked hemosiderin deposition (Figure 3). These findings supported our preoperative diagnosis of anterior mitral leaflet myxoma. This patient recovered without complication and was discharged 10 days after the operation. A 6-month follow-up TTE revealed normal left ventricular ejection fraction with only mild mitral regurgitation. DISCUSSION A left atrial myxoma was first described in a postmortem examination in 1845, however, the introduction of echocardiography has greatly facilitated the antemortem diagnosis of this tumor. 2,3) Myxoma, although rare, is the most common cardiac neoplasm in adults. 4,5) About 75% of myxomas originate in the left atrium, 15-20% in the right atrium, and only 3-4% in the ventricle. 6) Most myxomas arise from the interatrial septum at the border of the fossa ovalis. However, myxomas of the heart valve diagnosed during life are rare since the first report in ) The maximum dimension of mitral valve myxomas reported range from 0.5 to 3.5 cm. The myxoma of this patient was a large mass (5 4 3 cm) arising from the atrial side of the anterior mitral leaflet, which disturbed the hemodynam- Figure 3. Histopathological examination of the resected tumor. The lesion consisted of spindle-shaped and stellate cells in a capillary-rich area with a lymphocytic infiltrate and marked hemosiderin deposition.

5 Vol 44 No 3 MITRAL VALVE MYXOMA 433 ics as mitral stenosis induced lung congestion and pulmonary artery pressure elevation. These symptoms and signs improved quickly after removal of the myxoma. Embolization occurs in about 45% of patients with cardiac myxoma. 1) A review of the literature revealed that the diagnosis of left mitral myxoma was based on the findings of tumor embolization, suggesting that a myxoma in the mitral valve produces early embolization compared to other cardiac myxomas. In this case, the patient had only cardiac symptoms and signs, but not neurological and peripheral artery occlusion signs and symptoms, although brain and peripheral artery imaging was not performed. This may be because the myxoma of this patient was a well-defined encapsulated mass. In this case, the cardiac myxoma was diagnosed and located using TEE, and the results of operation and pathological examination supported the preoperative diagnosis. Although this myxoma was also found by TTE, an acoustic window and a tumor size less than 5 mm are the limitations of TTE. Thus, TEE may be useful to characterize the location and echostructure of cardiac tumors before an operation. Cardiac myxomas may recur postoperatively, and the real mechanism is unclear. Incomplete resection, intraoperative displacement, embolization, and multifocal genesis have been proposed as possible explanations. 10) Recurrence may occur within a few months to several years after the initial surgical excision and most are found during the first 4 years. In this case, to avoid local recurrence from the residual infiltrating myxoma tissue, extended resection through the leaflet around the tumor was performed when removing the myxoma. However, it has been reported that the overall risk of recurrence is about 1-3% for sporadic cardiac myxoma. 4,11) Thus, to detect early if the myxoma recurred in this patient, semiannual follow-up examinations using TEE are needed. 4) REFERENCES 1. Wold LE, Lie JT. Cardiac myxomas. A clinicopathologic profile. Am J Pathol 1980; 101: King TW. On simple vascular growths in the left auricle of the heart. Lancet 1845; 2: St John Sutton MG, Mercier LA, Giuliani ER, Lie JT. Atrial myxomas: a review of clinical experience in 40 patients. Mayo Clin Proc 1980; 55; Klaus R. Medical progress: cardiac myxomas. N Engl J Med 1995; 333: Kamiya H, Yasuda T, Nagamine H, et al. Surgical treatment of primary cardiac tumors: 28 year's experience in Kanazawa University Hospital. Jpn Circ J 2001; 65: McAllister HA Jr, Fenoglio JJ Jr. Tumors of the cardiovascular system. Atlas of Tumor Pathology. 2nd series. Fascicle 15, Washington, DC: Armed Forces Institute of Pathology. 1978: Sandrasagra FA, Oliver WA, English TA. Myxoma of the mitral valve. Br Heart J 1979; 42: Chakfe N, Kretz JG, Valentin P, et al. Clinical presentation and treatment options for mitral valve myxoma. Ann Thorac Surg 1997; 64:

6 434 CHEN, ET AL Jpn Heart J May Matsui Y, Shiya N, Marushita T, Yasuda K. Myxoma of the mitral valve prolapsing into the left atrium and ventricle; report of a case. Jpn J Surg 1998; 28: Sadeghi N, Sadeghi S, Karimi A. Mitral valve recurrence of a left atrial myxoma. Eur J Cardiothorac Surg 2002; 21: McCarthy PM, Piehler JM, Schaff HV, et al. The significance of multiple, recurrent, and complex cardiac myxomas. J Thorac Cardiovasc Surg 1986; 91: