Introduction

Cardiac tumours are very unusual and heart myxoma, which is generally a benign tumour, constitutes the most predominantly in heart. They actually represent 0.5 to 1 % of the tumours of soft tissues [₁]. The annual occurrence rate of this tumour is estimated at 0.5 / 1,000,000 / year [₂] and it is usually located in the left atrium (75%). It appears that its location in the right ventricle is rare [₃]. Here is the case of a patient presenting with a myxoma located in the right ventricle creating subsequently a partial obstruction of the outflow tract.

Case Report

A 13 years old girl previously healthy started 6 months ago to complain of dyspnea with was worsening with face oedema and swelling. She was referred to our clinic for stage III NYHA dyspnea. Two weeks ago, the situation got worse; requiring some cardiologic treatment and the patient was referred to cardio vascular surgery department. History did not show any myxoma case in her family. Physical examination revealed a bad general status and a clinical anaemia without fever. However the pulse rate was regular at 100 per minute; and the blood pressure was 100/60mmhg.

There was no longer an oedema on the face, but the pre-tibial oedema was still persistent associated with jugular veins distension and a hepatomegalia. Auscultation of the heart allowed a diagnosis of a pulmonary stenosis murmur, which was not varying with the changes of position. The patient did not present any neuro-endocrine clinical signs or any skin problems. The chest x-rays showed a convexity of the right mid arc, a cardiothoracic index of 60 % and a small left side empyema. The electrocardiogram showed a fast sinus rhythm.

The TTE [figure 1] showed a bi-lobal mass in the right ventricle measuring 4.4 x 2 cm with a sessile basis. The tumour was implanted on the antero lateral side of the right ventricle with an expansion into the pulmonary infundibulum, which was partially obstructs.

The right side cavities were dilated, and the right ventricle measured 44mm. The maximal gradient of right ventricle/pulmonary artery stood at 30mmhg whereas the mean gradient was 15mmhg. The systolic function of the left ventricle was normal with an ejection fraction of 70 %. The heart valves as well as the sub valvular apparatus were normal. Biology tests confirmed the clinical anaemia with haemoglobin at 9, 8 g/dl. The patient was operated within 48 hours following admission. Cardiopulmonary bypass was established with aorta and bicaval cannulas with moderate hypothermia, cold crystalloid cardioplegia was injected.

A longitudinal right atriotomy showed that the tricuspid valve was normal; the tumour was located in the anterior wall of the right ventricle. Excision of the mass was performed along with the pedicle. The tricuspid valve was continent after testing. Cross clamping time was 15 minutes and bypass 28 minutes. The anatomy pathological examination showed a myxoma like tumour with two lobes measuring 4.2 x 2.3 centimeters. At its top there were zones and muscular tissue and hemorrhagic necrosis. The evolution was uneventful; the early post operative TTE were satisfactory. Follow up TTEs after 3 months, 6 months and one year showed no signs of recurrence.

Figure 1

Figure 1: transthoracic echocardiography of the right ventricular myxoma.

Discussion

Myxoma constitutes the most frequent etiology of heart tumours; it represents 50% of benign heart tumours [₄₅]. Myxoma of the ventricles is rare. The occurrence of heart myxoma within patients of young patients should make suspect the Carney syndrome with associates myxoma diversely located, together with external skin problems (skin and mucous membrane lentiginosis, schwanomas and skin myxomas) and endocrine tumours [₆]. We have not seen those signs in the case of our patient, and there has never been a myxoma case in her family either.

In general myxoma are located in the left atrium (75%), statistics also indicate that 23% of myxoma is located in the right atrium whereas 2% are located in the ventricles on an equal distribution basis between the right and the left ventricle [₇]. The gravity of the myxoma is related to the risks of an arterial embolism, pulmonary embolism, but also the risk of obstruction of heart cavities or pulmonary obstruction in the right side locations. These potential risks for embolism occurrence correlates with the type of myxoma.There are two types of polypoid myxoma with crunchy surface and the myxoma with smooth surface. Polyploid tumour presents a higher potential risk for embolism. The size of the tumour is a factor that increases the potential risk for embolism [₈]. Our patient presented a large tumour (4.4 x 2cm), but the surface of the tumour was not that crunchy. The surgical excision has to be made with precaution; and any inconvenient manipulation of the tumour should be banned. There is a potential risk of pulmonary obstruction during the anaesthesia induction phase and during the sternotomy. The risk of splitting up the mass is real during the fixing of cannulas into the right atrium, if the tumour tends to pass into the auricle through the tricuspid valves.

We chose to set cannulas directly in the upper vena cava and then the lower vena cava, leaving the right atrium free, so the clamping of the pulmonary artery turned to be unnecessary. The right side atriotomy allowed us to expose the tumour through the tricuspid valve; the excision was realised without damaging the ventricular wall. Late relapses are rare regarding treatment of the simple forms if the excision is complete. Castello and col [₉] noted 0.4 in 5 % of recurrences occurring 22 years after surgery. However if previous myxoma cases had occurred in the family, the rate of recurrence is 40 %. Carney syndrom recurrences increase with young age, multiplicity in the location of the tumour and the family medical background. That is the reason why a follow-up through regular screening is mandatory for this young patient.

Conclusion

Myxoma of the right ventricle is rare and can be the etiology of right heart failure. To avoid the risk for pulmonary obstruction due to the tumour we decided to achieve a semi emergency excision. The age of the patient as well as the location of the tumour prompted us to practise a regular surveillance to watch for recurrences.

Correspondence to

Ciss Amadou Gabriel Chirurgie cardio-vasculaire CHN Fann BP 5035. Tel : 00 221 77 305 04 33 cissgaby@yahoo.fr