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Differential – diagnostic aspects of clinical presentations of cardiac tumors and acquired valvular disease

Irina Alexandrovna Zborovskaya – doctor of medical sciences, professor,cathedral professor of hospital therapy with the course of clinical rheumatology of the doctors improvement faculty of Volgograd state medical university, director of the Federal Budgetary State Institution (FBSI) “Research and development institute of clinical and experimental rheumatology” of the RAMS, head of the regional Osteoporosis Center, presidium member of the Association of rheumatologists of Russia, member of the editorial boards of the magazines “Scientific and practical rheumatology” and “Modern rheumatology” In general, primary as well as secondary tumors of the heart are rare. Cardiac neoplasms may be benign or malignant. The most common malignant myocardial tumor is cardiac sarcoma. The most common benign primary myocardial tumors are myxoma and rhabdomyoma, the latter usually arising from the heart muscle (that is granular cell [Abrikosov’s] tumor). Fibromas, lipomas and leiomyomas are less common. The other less common site is the pericardium. Myxoma. Myxomas are considered to be the most common tumors in patients aged 30 – 60 years. They occur less commonly in children and the elderly.  Myxomas tend to occur 3 times more often in women than in men. They are located on a narrow or broad base and are characteristically attached to the interatrial septum. Myxomas can also arise from cardiac valves. They are clinically manifested by a dense or jelly-like mass which may be either round or oval in shape and have an even or villiferous surface. Clumps of this mass may separate and cause arterial embolism which can be fatal. During the systole the tumor penetrates into the atrioventricular opening resulting in its stenosis or complete obstruction. Clinical presentations. Clinical presentations of myxomas are varying. Conventionally they are divided into:
  • clinical presentations which reflect the body’s response to tumor growth;
  • clinical presentations which are due to unfavourable effects of the tumor on the heart;
  • and clinical presentations which occur as a result of thromboembolic complications.
Cardiac myxoma and rheumatic heart disease have similar clinical presentations and laboratory findings. Myxoma of the left atrium may present with features suggesting mitral stenosis, while myxoma of the right atrium – with features of tricuspid stenosis. As rheumatic heart disease occurs more frequently than cardiac tumors, heart failure due to myxoma is often erronously taken for heart failure associated with rheumatic heart disease. It should be considered that the vast majority of myxomas develop from the left atrium, therefore, myxomas of the left atrium should be differentiated from mitral stenosis. The following differential findings should be considered: 1) Patients may differ in appearance. Patients with mitral stenosis and associated heart failure may have characteristic flushing. Patients with cardiac myxoma do not present with such features, however, heart failure is clearly marked. 2) Cardiac myxoma impairs blood flow through the atrioventricular opening and may cause its obstruction. In a vertical position myxoma approaches the atrioventricular opening resulting in its stenosis. The cases when a portion of the tumor penetrates through the atrioventricular opening into the left ventricle when the heart contracts have been reported. Temporary blood flow obstruction may be associated with syncope, chest pain, cyanosis, cough, shortness of breath. The symptoms typically subside when the person changes his body position. Some patients know the clinical situations which may precipitate such attacks and they try to avoid them. Depeding on the extent of severity of cerebral ischemia, the patient may develop blackouts, dizziness, syncope. Approximately ⅓ (one third) of patients with cardiac myxoma develop these symptoms. The symptoms develop when changing body position, especially from horizontal to vertical.  However, they may also occur capriciously. Syncopal episodes associated with mitral stenosis are usually present in patients with severe pulmonary hypertension. In cardiac myxoma syncopal episodes may not be associated with pulmonary hypertension or hypertrophy of the right ventricle. 3. 3.1. Heart failure associated with mitral stenosis typically develops some years after the onset of heart disease. The patient may report the character of the disease, recurrences of rheumocarditis and development of heart failure, its duration, severity, the state of health during remissions and rheumatic polyarthritis in past history. Heart failure associated with cardiac myxoma does not have such a wave-like course. Heart failure may be due either to the direct unfavourable effects on the contractile function of the myocardium or due to the conditions which interfere with the normal functioning of the heart as the main pump. Shortness of breath, hepatomegaly and edema normally develop within the first year after the onset of the disease. They are poorly pronounced, and even with treatment they cannot be cured. Heart failure associated with cardiac myxoma has a rapidly progressing course. Patients who exhibit the signs of cardiac myxoma typically do not have rheumatic polyarthritis or heart disease in the history. 3.2. Patients with heart failure associated with mitral stenosis always present with ciliary arrhythmia. Embolism of systemic circulation can be observed only in mitral stenosis complicated by ciliary arrhythmia or it may occur in rheumocarditis. Heart failure associated with myxoma of the left atrium typically develops in normal cardiac rate. Approximately 40% of patients with myxoma of the left atrium develop coronary embolism. More than 50% of patients develop cerebral vascular embolism. Thus, peripheral arterial embolism accompanied by sinus rhythm in patients without heart disease should aid the doctor in accurate diagnosis of myxoma or bacterial endocarditis and help him exclude these diseases. 3.3. Well pronounced hypertrophy of the right ventricle and enlargement of the left atrium are characteristic signs of tricuspid insufficiency associated with mitral stenosis. If there are no signs of acute rheumatic carditis, tricuspid insufficiency accompanied by mitral stenosis is typically associated with pronounced pulmonary hypertension. The extent of severity of tricuspid insufficiency is inconsistent with pulmonary hypertension in myxoma of the left atrium. 4. 4.1. Auscultative findings of mitral stenosis and myxoma of the left atrium are quite similar; however, thorough auscultation may reveal variable diastolic murmurs in myxoma of the left atrium. Their intensity and duration may change not only when changing body position from horizontal to vertical but also for unknown reason. However, the character of diastolic murmurs is not of great importance. It is their variability that indicates myxoma of the left atrium. Diastolic murmurs may be absent in aphonic mitral stenosis; however, when diastolic murmurs are heard, they are quite invariable. 4.2. Systolic murmurs in myxoma of the left atrium are much louder than diastolic murmurs. The combination of systolic and diastolic murmurs in mitral stenosis points to mitral insufficiency associated with hypertrophy of the left and right ventricles of the heart; however, in myxoma the ventricles are not enlarged. Myxoma may present without any electrocardiographic or X-ray findings of hypertrophied ventricles. Mitral valvular disease tends to have specific electrocardiographic and radiographic changes. 5) Paraneoplastic syndrome is considered to be a distinguishing characteristic of myxoma. Tumor growth may be associated with fever, changes of protein serum, moderate hypochromic anemia, elevated ESR (erythrocyte sedimentation rate), weight loss, polyserositis. The extent of markedness of the features which reflect the total body reaction to the growth of the tumor may vary. The body temperature may be slightly increased or may persist at 38-39 C. Depending upon the extent of severity of anemia and the extent of markedness of thromboembolic features as well as changes of globulin fraction of protein serum the clinical presentations which resemble those of bacterial endocarditis or recurrence of rheumatic carditis in patients with mitral stenosis may develop. 6) Specific laboratory and imaging studies are important in making the final diagnosis of myxoma of the left atrium in such doubtful situations. Echocardiography, especially cross-sectional, plays a fundamental role in topical diagnostics of cardiac myxoma. A-mode echocardiography may also indicate cardiac myxoma due to the silhouette of echo signals in the left atrium. Cross-sectional echocardiography makes it possible to distinguish the tumor and certain features of hemodynamics. Angiography might demonstrate the specific filling defects in the atrium. 7) Cardiac myxoma must be suspected in the following cases:
  • sudden detection of mitral valvular disease with a rapidly progressing course and unexpected recurrences in a patient without rheumatic diseases in the past history;
  • the extent of severity of clinical presentations of valvular disease is inconsistent with the small size of the heart; the link between the attack and a certain body position;
  • peripheral embolism in patients without pronounced clinical presentations of valvular disease, rhythm disturbances or bacterial endocarditis;
  • unexplained increase of body temperature, anemia, elevated ESR in patients with the above mentioned clinical presentations;
  • cardiac myxoma may be suspected if the radiologist reveals any cardiac calcifications or indirect symptoms of mitral stenosis.
Prognosis. Myxoma is a benign tumor, however, the elements of the tumor which seperate may metastasize to the adjacent structures. Inadequate removal of the peduncle of myxoma can cause recurrences. The average survival rate is 2 years, however, slow tumor growth and proliferation rates have been reported . In about 30% of cases sudden death occurs. The most common causes of death include severe blood circulation disturbances (pulmonary edema), severe pulmonary hypertension accompanied by acute prolonged pneumonia, severe rhythm disturbances, embolization of vital organs. In 12-15% of reported cases patients with cardiac myxoma do not develop any signs of tumor growth until fatal outcome or until a cardiac mass is identified by echocardiography. The cases of tumor malignization have been reported. Treatment. Surgical intervention is indicated to all patients with cardiac myxoma since pulmonary embolism or intractable pulmonary edema may occur at any time. The operation is performed with the use of artificial circulation. The surgery consists in complete surgical resection of the tumor together with its base. The defect in the interatrial septum is closed with a flap from the pericardium. If the valve is involved, it may require to be replaced.  Neither the patient’s age, nor the extent of decompensation caused by a large-sized tumor are considered as contraindications to surgical intervention. Rhabdomyoma. Rhabdomyomas account for approximately 20% of all benign cardiac neoplasms. It is a specific cardiac tumor because the skeletal muscle and the heart muscle are different in origin. It was not until 1862 that K. Rokitansky documented the presence of cardiac rhabdomyoma upon clinical examination. In Russia A.N. Abrikosov was the first to describe cardiac rhabdomyoma. Most primary rhabdomyomas are diagnosed in the first month or year of life. Rhabdomyomas are most often multiple. However, occasionally they can be in the form of a single node. Rhabdomyomas are tumors that most often arise from the left or right ventricles rather than the cardiac atria. Rhabdomyomas are typically found in the muscle thickness. However, they may also protrude either above the lumen of the cardiac cavity or under the epicardium. The size of the tumor ranges from barely noticable nodes to large-sized nodes which are clearly isolated from the cardiac muscle. Apart from a nodular form, there is also diffuse rhabdomyomatosis which stimulates hypertrophy of the cardiac muscle. Microscopically, the structure of rhabdomyoma is different from that of the normal cardiac muscle. It was not until 1909 that A.N. Abrikosov assumed that some rhabdomyomas arose from “detached cells” of the conduction system of the heart. Most researchers suppose that myocardial rhabdomyomas are specific hemartromas. There is some evidence, however indirect, that shows that rhabdomyomas most often occur in early childhood and in 60-70% of cases they are associated with certain congenital malformations. Benign tumors of the pericardium. Fibromas, lipomas, angiomas, teratomas and dermoid cysts belong to benign pericardial tumors. Most of them are asymptomatic and are typically identified postmortem. Large-sized pericardial tumors may be the cause of various disorders. Patients with a pericardial tumor may have an unpleasant sensation in the cardiac area. The tumor may also severely hinder the patient’s ability to work as the patient often develops shortness of breath, cough, diminished swallowing. The tumor may cause compression of heart chambers (most commonly one of the atria) or a large vessel (such as vein, aorta, pulmonary artery). The signs of blood circulation disturbances may also be noted. If the tumor compresses the condution tracts of the heart, rhythm disturbances may occur. Uneven heart enlargement is often revealed. Benign tumors may bleed into the cavity of the heart sac with cardiac tamponade. They may also cause sudden cardiac arrest and produce pericardial effusion (most commonly serous). Disease progression characteristically varies in different cases. For example: Angiomas are closely connected with the surrounding tissues and often bleed upon damage. These tumors most commonly bleed into the pericardial cavity resulting in sudden death. Angiomas may become malignant and spread to the adjacent structures. Fibromas are manifested clinically as a multiple small-sized multiforme polypous mass which resembles warts or villi. They are normally 2-3 cm in diameter and therefore, are unlikely to be detected upon clinical examination. Fibromas are typically asymptomatic. There are few blood vessels in fibromas and therefore, they never bleed. Lipomas present as small-sized asymptomatic masses. Occasionally, they are considered as the continuation of the adipose tissue of the atrial auricles and therefore, cannot be clearly distinguished. Obese patients may have clumps of fat deposits which resemble lipomas. In other cases lipomas may present as large-sized masses which may obstruct venous flow. Teratomas and dermoid cysts contain cavities which are filled with mucus. These cavities are lined with stratified epithelium which contains glandular masses. Cardiac teratomas may be large in size and can cause severe cardiac dysfunction. Along with this, teratomas may become malignant. Pericardial tumors are often associated with severe complications, therefore, the prognosis, even in benign pericardial tumors, is considered as unfavourable, when the tumor is large enough to be detected upon clinical examination. Malignant cardiac tumors. Primary cardiac sarcomas encompass a broad spectrum of tumors that includes fibrosarcomas, liposarcomas, angiosarcoma, including Kaposi’s sarcoma.
  • Rhabdomyosarcoma is considered as a malignant analogue of rhabdomyoma. However, all cardiac sarcomas are rare and only few have the structure which is similar to that of rhabdomyosarcoma.
  • Pericardium is one of the least common sites of malignant cardiac tumors. Most commonly they arise from the epicardium in the area of the transient fold.  Pericardial sarcomas and mesotheliomas are typically singled out. Pericardial sarcomas may be large in size and they rarely metastasize. Primary sarcomas of the heart sac (i.e. mesotheliomas) may cause thickening of the cardiac walls, the so-called “cancerous frosted heart”. They are small in size, most often metastasize to the lungs, pleura, mediastinal lymph nodes.
  • Metastatic cardiac and pericardial tumors are more frequent than primary malignant tumors. It is essential to know that lung and breast cancer metastasize to the heart in 40% of cases; melanoma in 33-50% of cases; malignant lymphoma – 15-37% of cases.
1. The main ways of tumor proliferation are hematogenous and lymphogenous. They may proliferate by means of direct extension of the adjacent tumors. Metastases may be found in the muscle thickness of the ventricles and atria. They may protrude above the lumen of the cardiac chamber and may spread to the pericardium. When the tumor spreads from the outside, the parietal pericardium is typically involved. The heart sac serves as the border of the tumor and makes it possible to leave the epicardium unaffected. 2. A nodular pattern of tumor proliferation is similar to that of a benign tumor and the tumor may be asymptomatic for a long period of time. Cardiac silhouette increases in one direction and it may seem either multicircuit or nodular. The heart typically displaces. 3. The tumor is manifested clinically by pericarditis which makes it even more complicated. 3.1. Pericarditis may be caused by a local actinic injury, especially when undergoing gamma- or radiotherapy in the mediastinal area at the dose of 25-40 gray in tumorous diseases. In this case recurrences of a pericardial tumor must be differentiated from postradiational pericarditis. The latter is often delayed by 1-5 years after irradiation and it may progress into recurrent pericarditis sicca, exudative pericarditis or constrictive pericarditis. 3.2. Tumorous pericarditis most commonly develops in adulthood, however, it may also occur in adolescents and even children (for example, sarcomas). The disease progression is slow, except for the cases when a disintegrating tumor penetrates through the heart sac. The course is typically afebrile. The patient usually develops the following symptoms: unpleasant sensation in the cardiac area, a sense of oppression or tightness in the chest which progresses into pain. Pericarditis is most often hemorrhagic; however, in 50% of cases the puncture does not reveal any traces of blood in the effusion. Pericarditis becomes hemorrhagic in the course of disease progression. A great amount of effusion accumulates in the cavity. In cancerous pericarditis lymphocytes make up 90% of leucocytes in the exudation. The exudation may also contain conglomerations of malignant cells. Cytologic studies represent a good diagnostic test for evaluating patients with tumorous pericarditis. 4. It should be noted that the erosive vessel may sometimes bleed or heart rupture may occur. Occasionally, the process may have a suppurative character or a compressing cancerous shell around the heart may develop. In this case the tumor affects the heart from all sides, thus forming a sac – the so-called “cancerous stone heart”. The disease resembles constrictive pericarditis as the tumor compresses the heart. This condition should be differentiated from tuberculous pericarditis and the other types of pericarditis. The tumorous process is characterised by a steady course, pericardial effusion and inefficiency of tuberculous or anti-inflammatory therapy.