Cardiac myxomas

Cardiac myxoma originating from the anterior mitral leaflet

Cardiac myxoma arising from the anterior mitral leaflet is extremely rare. A 47-year-old Taiwanese male was found to have a 5 x 4 x 3 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.

Atrial myxoma: case report and a review of the literature

Atrial myxomas are the most common benign primary tumor of the heart and occur in as many as 3 in 1000 patients. These tumors are a major cause of patient morbidity and mortality. Although the majority of atrial myxomas occur in the left atrium, 3 separate familial myxoma syndromes can result in multiple myxomas in atypical locations. Approximately 50% of patients with myxomas may experience symptoms due to central or peripheral embolism or intracardiac obstruction, but 10% of patients may be completely asymptomatic. Screening for myxomas should involve a thorough history and physical examination and a transthoracic and/or transesophageal echocardiogram. Transthoracic echocardiography is approximately 95% sensitive for the detection of cardiac myxomas, and transesophageal echocardiography approaches 100% sensitivity. Though the majority of atrial myxomas are sporadic, it is imperative that first-degree relatives of patients with documented myxomas undergo screening for occult myxomas. Surgical removal of the myxoma is the treatment of choice and usually curative; however, myxoma recurrence does occur and is most frequently associated with a familial syndrome.

Genetic testing of the family with a Carney-complex member leads to successful early removal of an asymptomatic atrial myxoma in the mother of the patient

Carney complex is a rare cardiocutaneous syndrome with an autosomal-dominant inheritance pattern. Apart from its cutaneous manifestations of multiple blue naevi and lentigines, it can involve multiple other organ systems, particularly the heart, where myxoma tumours commonly develop and can potentially lead to serious complications such as cerebrovascular accidents and myocardial infarction. Recently, a specific mutation in the gene encoding the R1-alpha regulatory subunit of cyclic adenosine monophosphate-dependent protein kinase A (PRKAR1alpha) has been discovered and found to be associated with a high risk of developing cardiac myxomas. We report the case of a Carney-complex family member who displayed no observable clinical or cardiac features of the disease but who was found to be positive for the PRKAR1alpha gene mutation on genetic testing. Further evaluation of this patient subsequently led to the discovery of a 3-cm atrial myxoma that had previously been undetected on cardiac assessment. This case highlights the potential benefits of using genetic screening for this disease.

Myxoma of the small bowel in a 47-year-old woman with a left atrial myxoma

Although atrial myxoma is the most common primary tumor of the heart, the synchronous occurrence of myxomas of the intestine and the heart has not been reported in the English literature. We report a case of a 47-year-old woman who presented with small bowel obstruction by a pedunculated mass that was found to be a myxoma after resection. A left atrial mass was found incidentally by a computed tomographic scan, and a diagnosis of atrial myxoma was confirmed after a second surgery. The cardiac myxoma showed classic histologic features, with tumor cells layered around vascular channels in an abundant myxoid matrix, while the small bowel lesion was less cellular. Immunohistochemical stains yielded identical results in both. No vascular involvement was noted at either site. This case supports the recommendation that a search for a cardiac lesion should be performed when a myxoma is identified at an unusual location.

[Cerebrovascular stroke as a sign of atrial myxoma in childhood]

Primary cardiac tumors are uncommon with an estimated incidence of between 0.0017 % and 0.19 %. Most are benign. Whereas myxomas are the most common primary tumor in adults, in children they are exceptionally rare. Cardiac myxomas usually develop in the left atrium, 20 % occur in the right atrium and the remainder develops in the ventricles and rarely in the heart valves. Cerebrovascular strokes secondary to myxoma are rare in childhood. The diagnostic test of choice is transesophageal echocardiogram and early excision is the most effective treatment in preventing serious complications. We report a case of cerebral stroke as the only manifestation of an atrial myxoma in an 11-year-old-girl. The patient presented vertigo, right hemiparesis of the body and dysarthria without loss of consciousness. After diagnostic tests (computerized tomography, magnetic resonance imaging and cerebral angioresonance) she was diagnosed with an ischemic lesion in the left middle cerebral artery. Various investigations were performed to find the cause of the stroke, among them cardiologic study, and a mass in the left atrium suggestive of myxoma was found. The tumor was removed and the diagnosis of myxoma was confirmed by histopathological examination. Outcome was satisfactory. The presence of a cerebral ischemic episode, with or without concomitant heart disease, suggests the need to look for cardiac etiology.

Role of magnetic resonance imaging for evaluation of tumors in the cardiac region

The aim of this study was to review the role of MRI in the assessment of heart neoplasm, 25 cases with heart neoplasm (10 myxoma, 6 rhabdomyoma, 5 angiosarcoma, 2 mesothelioma, 1 lymphoma, and 1 fibroma) were examined with MRI and echocardiography. Multislice T1- and T2-weighted spin-echo images and static gradient-echo images were taken in appropriate directions with electrocardiogram gating. Gadolinium enhancement was performed in 21 cases. Transthoracic echocardiography was performed in all cases. Except for the 5 patients with rhabdomyoma, the pathological diagnosis was obtained. MRI proved to be useful for tissue characterization of myxoma, angiosarcoma, mesothelioma, and fibroma in cases with tuberous sclerosis. MRI also proved to be useful for detection of the tumor, depiction of contour, relation with other cardiac structures, in cases with myxoma, angiosarcoma, mesothelioma, lymphoma, and fibroma. In the differential diagnosis, MRI provided important information in cases with myxoma, rhabdomyoma, angiosarcoma, and fibroma. In cases with tumors expanding into the mediastinum, such as mesothelioma and fibroma in this report, MRI was useful in determining the location and border. In cases with tumors adjacent to pericardium, MRI was useful in detecting pericardial invasion. Gadolinium enhancement added useful information in cases with myxoma, rhabdomyoma, angiosarcoma, and mesothelioma. The role of MRI with and without Gd enhancement differs somewhat in individual types of heart neoplasm, and adaptation must be considered in each kind of neoplasm. On the other hand, MRI is an essential examination in all cases with a cardiac mass, which has not been diagnosed, since it may provide useful information for the differential diagnosis.

Left hemiparesis from atrial myxoma emboli

Atrial Myxomas are benign primary tumors of the heart, arising mainly from the left atrium. Clinical signs and symptoms produced by atrial myxomas may be non-specific or result in mechanical obstruction of cardiac function, arrhythmias, and embolization. The authors present a case of a 60-year-old woman who developed total left hemiparesis resulting from left atrial myxoma embolization causing complete occlusion of the right middle cerebral artery.

Assessment of the vascularity of a left ventricular mass using myocardial contrast echocardiography

In addition to a thrombus, an intracardiac mass lesion can represent a primary cardiac tumor, or a metastatic lesion to the heart. The echocardiographic appearance and location of the mass, as well as the associated clinical scenario provide useful clues regarding cause, but these echocardiographic features alone may not always be diagnostic. Because most benign cardiac tumors are relatively avascular, the vascularity of a mass may be a feature that can help differentiate benign from malignant tumors. We present a case of a patient with a history of malignant melanoma who was found incidentally to have a cardiac mass on echocardiography. Contrast echocardiography (CE) was used to evaluate the vascularity of the mass. This case is compared with another patient with an apical thrombus, which represents an "avascular" intracardiac structure.

Trends in the clinical and morphological characteristics of cardiac myxoma: 20-year experience of a single tertiary referral center in Japan

The purpose of this study was to clarify whether or not a change in the clinical characteristics of cardiac myxoma has occurred during the past 2 decades. The clinical records of 57 patients (22 men, 35 women; age, 52+/-14 years) with myxoma that had been surgically treated between May 1978 and July 1997 at the National Cardiovascular Center in Japan were reviewed. All myxomas were discovered by transthoracic echocardiography. They were divided into an early group (n=30) treated in the first decade (1978-1987) and a late group (n=27) treated in the second decade (1988-1997). The incidence of myxoma, patient characteristics, preoperative symptoms and echocardiographic features did not differ between the 2 groups. In contrast, the maximal dimensions of myxoma in the early group were significantly larger than those in the late group (6.3 +/-2.7 cm vs 4.3+/-1.3 cm, p=0.012). The weight of myxoma in the early group tended to be heavier than that in the late group (76+/-80 g vs 25+/-18 g, p=0.054). The incidence of patients with asymptomatic myxoma also tended to increase in the late group (7% vs 26%, p=0.07). Although there was no difference in the incidence of myxoma, smaller and asymptomatic myxomas were more frequent during the last decade, probably as a result of the development of cardiac imaging, particularly echocardiography.

Cardiomyogenic differentiation in cardiac myxoma expressing lineage-specific transcription factors

We investigated five cases of cardiac myxoma and one case of cardiac undifferentiated sarcoma by light and electron microscopy, in situ hybridization, immunohistochemical staining, and reverse transcriptase-polymerase chain reaction for cardiomyocyte-specific transcription factors, Nkx2.5/Csx, GATA-4, MEF2, and eHAND. Conventional light microscopy revealed that cardiac myxoma and sarcoma cells presented variable cellular arrangements and different histological characteristics. Ultrastructurally, some of the myxoma cells exhibited endothelium-like or immature mesenchymal cell differentiation. Immunohistochemistry for Nkx2.5/Csx, GATA-4, and eHAND was slightly to intensely positive in all myxoma cases. MEF2 immunoreactivity was observed in all cases including the case of sarcoma, thus suggesting myogenic differentiation of myxoma or sarcoma cells. In situ hybridization for Nkx2.5/Csx also revealed that all myxoma cells, but not sarcoma cells, expressed mRNA of the cardiac homeobox gene, Nkx2.5/Csx. Furthermore, nested reverse transcriptase-polymerase chain reaction from formalin-fixed, paraffin-embedded tissue was performed and demonstrated that the Nkx2.5/Csx and eHAND gene product to be detected in all cases, and in three of six cases, respectively. In conclusion, cardiac myxoma cells were found to express various amounts of cardiomyocyte-specific transcription factor gene products at the mRNA and protein levels, thus suggesting cardiomyogenic differentiation. These results support the concept that cardiac myxoma might arise from mesenchymal cardiomyocyte progenitor cells.

Cutaneous embolization of cardiac myxoma

Atrial myxoma is the most common primary tumour of the heart. Skin manifestations in patients with a cardiac myxoma are frequent and may be due to cutaneous emboli, or may be specific findings as part of more complex syndromes. We present a 33-year-old-man with a history of episodes of pain in both legs and an ischaemic neurological event, who also had episodes of acral papular erythematous lesions on the legs and feet including the soles. The histological finding of dermal vessels occluded by a myxomatous material was the clue to the diagnosis of a cardiac myxoma. The diagnosis of this entity can be very difficult, because of the broad spectrum of clinical features; rarely the skin manifestations lead to the diagnosis of this tumour. The histological recognition of the myxomatous emboli is of vital importance for the diagnosis and treatment of this disease.

Intraoperative diagnosis of an unsuspected left atrial myxoma by transesophageal echocardiography

IMPLICATIONS

The authors report the intraoperative diagnosis using transesophageal echocardiography (TEE) of an unsuspected myxoma in a patient admitted for an acute occlusion of the aorta, resulting in emergency excision of the atrial tumor. This observation illustrates the usefulness of intraoperative TEE examination to identify life-threatening pathology.

Intramural cardiac myxoma in left ventricular wall: an unusual location

A 27-year-old asymptomatic woman was investigated for an abnormal finding in the cardiac contour on routine chest radiography. Echocardiography revealed a heterogeneous mass in the anterolateral left ventricular wall. Excision of the tumor disclosed an absence of communication between the residual cavity and the left ventricular endocardium. Histological features of the tumor indicated an intramural myxoma.

Spontaneous resolution of obstructive valvular tumors in infants

BACKGROUND

Myxomas, the most common cardiac tumor in adults, occur in the atria and are prone to embolization. Obstructive valvular tumors in infants occur in pulmonic and aortic valves and generally have a more benign course.

METHODS

We conducted a review of our experience in infants with tumors obstructing the right or left ventricular outflow tract, originating from pulmonic or aortic valve tissue. Tissue diagnosis was available from only the index case; 4 additional infants survived with spontaneous regression, and only echocardiographic characterizations were available.

RESULTS

Five cases were found with obstructing valvular tumors. In the index case, the obstruction resulted in heart failure, required surgical extirpation, and revealed histology diagnostic of a myxoma. In the subsequent 4 infants with conditions diagnosed with echocardiography, the appearance was suggestive of myxomas (small, compact, ovoid, with no fronds and no embolization). All 4 cases remained mildly to moderately obstructive and then showed spontaneous regression during a period of months to years.

CONCLUSION

None of our cases deteriorated clinically, except the first, and were therefore different from other tumors, such as adult atrial myxomas, papillary fibroelastomas, fibromas, and rhabdomyomas. Only the latter are known to spontaneously regress in infancy. The prevalence of valvular tumors in infants may have previously been underestimated, given the absence of symptoms in 4 of our cases and the spontaneous regression of the tumor. An alternate diagnosis for these 4 cases could be a tissue "myxomatous rest" as opposed to a neoplastic myxoma. In either case, surgical intervention may not be necessary.

Long-term survival of quiescent left atrial myxoma in an elderly patient

Left atrial myxoma, if left untreated, is inexorably progressive and usually fatal. The classical management of this disease is prompt surgical removal. However, there may be exceptions to this traditional dogma. The authors report an 85-year-old man who presented with features of chronic obstructive airway disease and congestive heart failure 15 years previously. Auscultation of the heart showed a pansystolic murmur. Two-dimensional echocardiography revealed a nonobstructive, calcified, and well circumscribed mass in the left atrium, with a pedicle attached to the interatrial septum. Because the patient refused high-risk cardiac surgery related to his comorbidity, he was managed medically with a bronchodilator, diuretics, and digoxin. There have been no features of embolism or intracardiac obstruction, and serial echocardiography demonstrates no disease progression over this long period of time. This case illustrates that calcified left atrial myxoma may exhibit a quiescent phase. Tumor calcification, slow growth potential, and the absence of intracardiac obstruction may correlate with a better outcome in the elderly patient.

[Cardiac myxoma. Clinical-pathological correlation]

INTRODUCTION AND OBJECTIVES

Myxomas are the most common type of primary cardiac tumors. The aim of this study was to analyze the clinical forms of presentation of cardiac myxoma, the postoperative evolution, and the possibility of recurrence and tumoral embolism.

PATIENTS AND METHOD

From July 1992 to March 1999, 31 patients with myxoma were studied. Cell cycles (ploidy pattern of the tumoral DNA) were studied in 12 patients to evaluate the risk of recurrence and tumoral embolism.

RESULTS

The most frequent clinical manifestations were constitutional symptoms (74%), dyspnea (45%), and embolism (41%). Smaller-diameter myxomas correlated independently with tumoral embolism (45%). The in-hospital mortality was 3.2%, no deaths were observed during follow-up (mean: 4.8 years). No patients had clinical or echocardiographic signs of tumoral recurrence. Patients with tumoral embolism (n = 8) were compared with patients without embolism (n = 4). Patients who suffered embolism had higher S phase > 7 and/or DNA index > 1.2 (4/4 patients [100%], p= 0.061) than patients without embolism (2/8 patients [25%]). Cytometry of the only recurrent tumor (second operation) revealed a diploid tumor with a significantly more frequent S phase (10%) than in sporadic myxomas (4.27 2.32%, p = 0.039).

CONCLUSIONS

Constitutional symptoms, dyspnea, and tumor embolism were the most frequent clinical manifestations. Clinical and anatomopathologic characteristics and the cell cycle were not significantly related to tumoral embolism, but there was a tendency toward a higher proportion of cells in S phase and a higher DNA index in tumors associated with embolism. The S phase was significantly more frequent in the only case of recurrent myxoma and could be a potential marker of recurrence.

Cardiac myxoma: imaging features in 83 patients

Eighty-six cardiac myxomas were reviewed retrospectively for the clinical, pathologic, and radiologic findings. In this series, 83 patients (47 female and 36 male; age range, 2-78 years; mean age, 48 years) had 49 left atrial (60%), 23 right atrial (28%), seven right ventricular (8%), two biatrial, and two cases of multifocal myxomas. Seventy-one (88%) patients were symptomatic. Radiographs of 38 patients with left atrial myxoma showed evidence of mitral valve obstruction in 53%; radiographs of 16 patients with right atrial myxoma demonstrated calcification and cardiomegaly in 56% and 50%, respectively. Computed tomographic (CT) scans of 21 myxomas demonstrated 20 (95%) spherical or ovoid lesions, 16 (76%) with lobular borders. Seventeen (81%) were hypoattenuated; 14 (67%) were heterogeneous. Twenty-eight magnetic resonance (MR) imaging studies of 30 myxomas showed 29 (97%) spherical or ovoid lesions; 26 (87%) had lobular contours and 26 (90%) of 29 had heterogeneous signal intensity on T1-weighted images. Point of attachment was visible in 15 (83%) cases. Cine gradient recalled echo (GRE) MR images of 10 lesions showed low signal intensity in all cases. Most patients with cardiac myxomas have abnormal but usually nonspecific radiographic findings. CT demonstrates intracavitary heterogeneous, hypoattenuated lobular masses. MR imaging shows heterogeneous lobular lesions and usually allows visualization of the point of attachment. Radiologic imaging of these lesions, particularly with multiplanar and cine GRE MR imaging, can provide accurate assessment of the size, location, and point of attachment of these lesions and should assist in surgical planning.

Mechanisms of cardioembolic stroke

Cardiac embolism is often involved as a mechanism for embolic stroke, and may be implicated in many strokes that have traditionally been considered of unknown origin (cryptogenic strokes). In recent years, significant advancements have been made in understanding and reducing the risk of stroke from long-known cardioembolic sources (atrial fibrillation, intracardiac thrombus or tumor, infective endocarditis). Also, improved cardiac imaging, especially transesophageal echocardiography, has allowed the identification of newer embolic sources of stroke (aortic atheromas, patent foramen ovale, atrial septal aneurysm). This article reviews the current understanding of cardiac embolism as a mechanism for stroke, and the preventive options that are currently adopted to decrease the stroke risk.

Pseudovasculitis: mechanisms of vascular injury and clinical spectrum

Pseudovasculitis, vasculitis-like syndromes, or mimics of vasculitis represent a heterogeneous collection of disorders that are capable of simulating a vasculitic disorder. Some conditions such as cardiac myxomas, cholesterol embolization, and fibromuscular dysplasia are more apt to cause confusion, but numerous other conditions can do so also. Inappropriate diagnosis leads to delay or absence of proper management and exposure to potentially deleterious treatment modalities such as corticosteroids and cytotoxic agents. The diagnosis of a pseudovasculitic disorder requires a high index of suspicion and should always be part of the differential diagnosis of vasculitis. The endothelium is thought to be pivotal in vascular injury; much has been learned using in vitro human umbilical vein endothelial cell cultures. Application of this knowledge to human disease and to vasculitic disorders and their imitators is still premature.

Right Atrial Myxoma Arising from Crista Terminalis in Septuagenarian

A right atrial myxoma arising from the crista terminalis was detected during follow-up echocardiography in a 74-year-old man who had undergone coronary artery bypass grafting one year earlier. The myxoma was excised en bloc with a wide cuff of normal atrial wall and the right atrium was reconstructed with autologous pericardium.

Infected left atrial myxoma

Upon examination, a 40-year-old man was found to have fever, weight loss, and malaise. A blood culture was positive for Streptococcus mutans. Under the suspicion of endocarditis, he was treated with penicillin. Echocardiography revealed a large tumor in the left atrium. After 6 weeks of penicillin treatment, he was transferred to our hospital for excision of the tumor. Pathology revealed a myxoma with fibrin deposits, bacterial colonization, and massive infiltration with neutrophils.

Cardiac papillary fibroelastoma on the pulmonary valve: a rare cardiac tumor. okaken@mcai.med.hiroshima-u.ac.jp

We report the case of a patient with a rare papillary fibroelastoma on the pulmonary valve visualized before surgical intervention. The tumor was an encapsulated, rounded mass. The gelatinous membrane on the surface tore easily, and multiple fronds appeared. This case emphasizes that when there is an encapsulated mass attached to a valve, the initial excision of valve tissue should be as minimal as possible. To avoid unnecessary injury to the valve, it is simple and practical to confirm that the tumor has the appearance of a sea anemone, thus identifying it as a papillary fibroblastoma, a benign tumor.

Clinical presentation of left atrial cardiac myxoma. A series of 112 consecutive cases

We analyzed a series of 112 consecutive cases of left atrial myxoma diagnosed in a single French hospital (72 women and 40 men; age range, 5-84 yr) over 40 years, from 1959 to 1998. Symptoms of mitral valve obstruction, the first arm of the classic triad of myxoma presentation, were present in 75 patients (67%), with mostly cardiac failure or malaise. Symptoms of embolism, the second frequent presentation in the classic triad, were observed in 33 cases (29%) with 1 or several locations, essentially cerebral emboli with stroke. Males are statistically at greater risk than females of developing embolic complications. The third arm of the classic triad consists of constitutional symptoms (34%) with fever, weight loss, or symptoms resembling connective tissue disease, due to cytokine (interleukin-6) secretion. Younger and male patients have more neurologic symptoms, and female patients have more systemic symptoms. Seventy-two patients (64%) had cardiac auscultation abnormalities, essentially pseudo-mitral valve disease (53.5%) and more rarely the suggestive tumor plop (15%). The most frequent electrocardiographic sign was left atrial hypertrophy (35%), whereas arrhythmias were uncommon. The greater number of myxoma patients (98) diagnosed preoperatively after 1977 reflects the introduction of echocardiography as a noninvasive diagnostic procedure. However, there was no significant reduction in the average time from onset of symptoms to operation between patients seen in the periods before and after 1977. The tumor diameter ranged from 1 to 15 cm with a weight of between 15 and 180 g (mean, 37 g). The myxoma surface was friable or villous in 35% of the cases, and smooth in the other 65% cases. Myxomas in patients presenting with embolism have a friable surface; those in patients with cardiac symptoms, pseudo-mitral auscultation signs, tumor plop, and electrocardiogram or radiologic signs of left atrium hypertrophy and dilatation are significantly the larger tumors. The long-term prognosis is excellent, and only 4 deaths occurred among our 112 cases over a median follow-up of 3 years. The recurrence rate is low (5%), but long-term follow-up and serial echocardiography are advisable especially for young patients.

Tumors and the heart: molecular genetic advances

Recent molecular genetic investigations of primary cardiac tumors (myxomas, lipomas, rhabdomyomas, and fibromas) have provided insight into fundamental mechanisms of cardiac cell growth. Myxomas are the most common adult cardiac tumor, and familial cardiac myxomas are now appreciated to be caused by mutations in the PRKAR1alpha gene that encodes a regulatory subunit of protein kinase A. Cytogenetic studies have targeted candidate chromosomal loci that may be perturbed during cardiac lipoma pathogenesis. Rhabdomyomas, the most common pediatric cardiac neoplasm, are frequently associated with tuberous sclerosis, caused by mutations in the TSC-1 and TSC-2 genes. The study of Gorlin syndrome has shed light on the etiology of cardiac fibromas. This disorder is caused by mutation of the PTC gene, which regulates cell growth, commitment and differentiation. In the future, manipulation of PRKAR1alpha-, TSC-, and PTC-dependent pathways may foster new strategies to regenerate myocardium in the ischemic or myopathic heart.

Fatal cerebral embolism in a young patient with an occult left atrial myxoma

We report a young patient with a fatal cerebral embolism from an occult atrial myxoma. The patient died before echocardiography was performed and at autopsy the definite diagnosis was made. Our patient suffered from migraine of increasing frequency. The physical exercise of sexual intercourse was the precipitating factor of this fatal embolism. The importance of early echocardiography is stressed, especially in view of the recent tendency of early and aggressive stroke treatment.

Ras oncogenes and p53 tumor suppressor gene analysis in cardiac myxomas

Although ras oncogenes and p53 tumor suppressor gene mutations are implicated in the development of several human tumors, little is known about their role in the pathogenesis of primary cardiac tumors. Paraffin-embedded tissue from 19 cardiac myxomas were investigated for the presence of ras oncogenes and p53 tumor suppressor gene abnormalities. Immunohistochemical analysis was used to identify the accumulation of p21-ras and p53 proteins. A polymerase chain reaction was used to amplify exons 1 and 2 of the ras genes and exons 5 to 8 of the p53 gene. The PCR products were analyzed by single strand conformation polymorphism analysis and by direct DNA sequencing. Three of 19 myxomas showed strong positive staining for the ras p21 protein. In contrast, nuclear p53 was not detectable in any of the myxomas. Among the ras p21 immunopositive myxomas, 2 were heterozygous for a missense point mutation of the K-ras, Gly 12Asp. Further screening of the remaining myxomas showed no mutation or even silent polymorphism in any exon of the ras and p53. The results suggest that although genetic alterations of ras oncogenes and p53 are uncommon events in cardiac myxomas, ras mutations may be involved in the pathogenesis of a subgroup of this type of tumor.

Saddle embolus--the need for intensive investigation and critical evaluation: a case report

Embolic aortoiliac occlusion is associated with high mortality and morbidity rates. In this case of saddle embolism the embolic source was identified only by persistent investigation, and the importance of investigation is highlighted.

Imaging of cardiac and paracardiac masses

Magnetic resonance imaging (MRI) and computed tomography (CT) are important imaging modalities for the noninvasive characterization of cardiac and paracardiac masses. They are, in general, superior to other modalities (e.g., echocardiography) in their ability to delineate the exact location and the extent of the lesion and to demonstrate the effects of the lesion on surrounding structures. MRI and CT may also be helpful in suggesting a specific diagnosis, because some tumors have rather characteristic locations and appearances. In addition, both modalities can be extremely helpful in both treatment planning and posttreatment follow-up because they are noninvasive, reproducible, and enable detection of residual or recurrent mass.

CT and MR imaging of benign primary cardiac neoplasms with echocardiographic correlation

Benign primary cardiac neoplasms are rare but may cause significant morbidity and mortality. However, they are usually treatable and can often be diagnosed with echocardiography, computed tomography (CT), or magnetic resonance (MR) imaging. Myxomas typically arise from the interatrial septum from a narrow base of attachment. Fibroelastomas are easily detected at echocardiography as small, mobile masses attached to valves by a short pedicle. Cardiac fibromas manifest as a large, noncontractile, solid mass in a ventricular wall at echocardiography and as a homogeneous mass with soft-tissue attenuation at CT. They are usually homogeneous and hypointense on T2-weighted MR images and isointense relative to muscle on T1-weighted images. Paragangliomas usually appear as large, echogenic left atrial masses at echocardiography and as circumscribed, heterogeneous masses with low attenuation at CT. These tumors are usually markedly hyperintense on T2-weighted MR images and iso- or hypointense relative to myocardium on T1-weighted images. Cardiac lipomas manifest at CT as homogeneous, low-attenuation masses in a cardiac chamber or in the pericardial space and demonstrate homogeneous increased signal intensity that decreases with fat-saturated sequences at T1-weighted MR imaging. Cardiac lymphangiomas manifest as cystic masses at echocardiography and typically demonstrate increased signal intensity at T1- and T2-weighted MR imaging. Familiarity with these imaging features and with the relative effectiveness of these modalities is essential for prompt diagnosis and effective treatment.

Mutations in the protein kinase A R1alpha regulatory subunit cause familial cardiac myxomas and Carney complex

Cardiac myxomas are benign mesenchymal tumors that can present as components of the human autosomal dominant disorder Carney complex. Syndromic cardiac myxomas are associated with spotty pigmentation of the skin and endocrinopathy. Our linkage analysis mapped a Carney complex gene defect to chromosome 17q24. We now demonstrate that the PRKAR1alpha gene encoding the R1alpha regulatory subunit of cAMP-dependent protein kinase A (PKA) maps to this chromosome 17q24 locus. Furthermore, we show that PRKAR1alpha frameshift mutations in three unrelated families result in haploinsufficiency of R1alpha and cause Carney complex. We did not detect any truncated R1alpha protein encoded by mutant PRKAR1alpha. Although cardiac tumorigenesis may require a second somatic mutation, DNA and protein analyses of an atrial myxoma resected from a Carney complex patient with a PRKAR1alpha deletion revealed that the myxoma cells retain both the wild-type and the mutant PRKAR1alpha alleles and that wild-type R1alpha protein is stably expressed. However, in this atrial myxoma, we did observe a reversal of the ratio of R1alpha to R2beta regulatory subunit protein, which may contribute to tumorigenesis. Further investigation will elucidate the cell-specific effects of PRKAR1alpha haploinsufficiency on PKA activity and the role of PKA in cardiac growth and differentiation.

An interleukin-6-producing cardiac myxoma associated with mediastinal lymphadenopathy

We report our experience with a patient whose mediastinal lymphadenopathy resolved after resection of a cardiac myxoma that secreted interleukin-6 (IL-6). The patient was a 68-year-old female who complained of nocturnal chest discomfort related to congestive heart failure. An echocardiogram demonstrated a large left atrial mass. A computed tomogram showed not only the left atrial mass but multiple enlarged mediastinal lymph nodes. The serum IL-6 level was markedly elevated at 13.7 pg/ml. After resection of the cardiac myxoma, serum IL-6 returned to the normal range. A repeat computed tomogram showed no mediastinal lymphadenopathy. We believe that overproduction of IL-6 by the cardiac myxoma was the cause of the mediastinal lymphadenopathy.

Myxoma involving the atrial valve chordae

Primary cardiac valve tumors are rare and comprise less than 10% of all cardiac tumors. They are, however, of clinical importance because of their unique locations. We report an unusual case of myxoma involving the tricuspid valve chordae in a young woman presenting with syncope. The myxoma was diagnosed by echocardiography and successfully removed by excision of the involved tricuspid valve chordae with valve preservation. (Curr Surg 57:357-358)

Histopathologic and clinical characterization of cardiac myxoma: review of 53 cases from a single institution

BACKGROUND

Cardiac myxomas have varying clinical presentation, uncertain histogenesis, and debatable immunohistochemical profile. A few malignant cases have been previously reported.

METHODS

Fifty-three consecutive cardiac myxomas were histologically investigated and results compared with clinical data. The main goal of the study was to investigate the immunohistochemical differentiation and the clinicopathologic correlations.

RESULTS

Stromal cells were characterized by the expression of the von Willebrand factor endothelial marker (12 of 53 cases) and diffuse cytoplasmic neuropeptides such as protein gene product 9.5 (50 of 53 cases), S100 protein (47 of 53) and neuron-specific enolase (30 of 53), all of which were expressed in 30 (57%) of 53 tumors. Stromal cells did not show endocrine granules, epithelial, or smooth muscle immunoreactivity. Non-cardiac-related symptoms were observed in 7 of 53 patients and promptly disappeared after tumor excision; median values and percentages of total immunoreactivity scores for neuropeptides were higher in these 7 cases, but data analysis showed no statistical significance. Glands were detected in 2 myxomas, and they showed epithelial (cytokeratins and carcinoembryonic antigen), protein S100, and neuron-specific enolase immunoreactivity; this pattern has been previously detected in human gut. All tumors showed benign behavior, and no mitosis was detected.

CONCLUSIONS

The results of this study support the hypothesis that stromal cells originate from multipotent mesenchyme capable of neural and endothelial differentiation; rare myxoma glands would represent entrapped foregut rests. A correlation could exist between neuroendocrine differentiation and non-cardiac-related symptoms.

Stroke and Myxoma

Cardiac myxoma was detected by transthoracic echocardiography in 8 patients (aged 11 to 64 years) who were admitted between 1991 and 1999 with stroke or transient ischemic attacks, representing 80% of the total myxoma cases treated in this period. All patients underwent surgery and the myxomas were successfully removed. There were no recurrences during a mean follow-up of 3.1 years. In the presence of unexplained transient ischemic attack, cerebral infarction, or syncope, this relatively rare cardiac lesion should be suspected and investigated by transthoracic echocardiography.

Cardiovascular effects of an immunosuppressive agent cyclosporin A

Cyclosporin A (CsA) is now routinely used for transplantation of all solid organs, bone marrow transplantation, and for an increasing number of immunological diseases. However, treatment with CsA is an important iatrogenic cause of post-transplant hypertension, hyperlipidemia, and diabetes, which may contribute to the high cardiovascular morbidity in transplant recipients. Recently, the calcineurin inhibitor CsA has been employed in vivo and in vitro to examine the role of calcineurin in the signal transduction leading to cardiac hypertrophy. A cell culture study demonstrated the inhibitory effect of CsA on cytokine production by cardiac myxoma cells, the most common primary tumor of the heart. This review discusses recent data on the cardiovascular effects of CsA.

Stroke prevention: cardiac and carotid-related stroke

The aim of this article is to discuss cardiac sources of stroke as well as the management of symptomatic and asymptomatic carotid stenosis. The authors detail the risks of cardioembolic stroke in the following conditions: aortic arch atheroma, atrial fibrillation, atrial myxoma, atrial septal aneurysm, dilated cardiomyopathy, infective endocarditis, left ventricular thrombus, mitral annular calcification, mitral valve prolapse, patent foramen ovale, prosthetic heart valves, valvular strands, and the optimal medical management for these conditions. The indications for carotid endarterectomy, angioplasty, and stenting are also outlined.