Hamartomas of mature cardiac myocytes: report of 7 new cases and review of literature

Third Trimester Stillbirth Associated With Hamartoma of Mature Cardiac Myocytes (HMCM)

Fetal primary cardiac tumors (FPCTs) are very rare. The majority of them correspond to cardiac rhabdomyomas, followed by other benign neoplasms or hamartomas. We describe the case of a third trimester female stillborn with an incidental autopsy finding of Hamartoma of Mature Cardiac Myocytes (HMCM), a rare benign cardiac tumor previously unreported in the fetal or neonatal period. The intrauterine demise occurred at 32 + 6 weeks gestation after an uneventful pregnancy. The fetal autopsy revealed a structurally normal heart with a small subendocardial nodule just below the membranous septum. Microscopically, the nodule was well-demarcated from the surrounding penetrating bundle of the conduction axis and the adjacent left ventricular myocardium and consisted of disorganized mature cardiac myocytes in a haphazard arrangement with patchy mild interstitial fibrosis, consistent with HMCM. Awareness that HMCM can occur in the fetus is important in order to consider it among the differential diagnosis of FPCTs.

Hamartoma of mature cardiac myocytes presenting as a polypoid epicardial tumor in the interatrial groove and with gene fusions by copy number anomalies of chromosome 7

Hamartoma of mature cardiac myocytes (HMCM) is an extremely rare cardiac tumor characterized by benign growth of differentiated mature striated cardiac myocytes, and usually involves the ventricular myocardium. We describe the case of a 15-year-old female who presented with a short history of atrial fibrillation and a polypoid epicardial tumor that was attached to the interatrial groove by a short pedicle. The resected specimen showed features consistent with HMCM. Although these tumors are not associated with any known molecular or cytogenetic abnormalities, we identified fusions transcripts along with complex copy number anomalies of chromosome 7.

A Rare Septal Hamartoma of Mature Cardiac Myocytes Manifesting With Cardiac Cachexia in a Teenager

Hamartomas of mature cardiac myocytes are a rare type of primary cardiac tumor, with only 5 cases of interventricular septal involvement reported to date. They are often challenging to diagnose, and there is currently no standardized approach to surgical resection. Here, we present a rare case of a large 6.0 × 4.4 × 3.8-cm interventricular septal hamartoma that manifested with cardiac cachexia in a teenage patient. Surgical biopsy was used after 4 attempts at endomyocardial biopsy were nondiagnostic, and partial debulking was performed as complete resection was not feasible.

Hamartoma of Mature Cardiac Myocytes: Systematic Review

BACKGROUND

While primary cardiac tumors are rare, it has been increasingly recognized due to improvement in screening measures. However, the hamartoma of mature cardiac myocytes has been underrecognized compared to other cardiac tumors, such as cardiac myxomas and papillary fibroelastomas, and is still potentially associated with critical consequences such as sudden death. This systematic review aims to summarize the evidence regarding the hamartoma of mature cardiac myocytes and characterize the presentations and symptoms for clinicians.

METHODS

Following the PRISMA statement, we searched MEDLINE and EMBASE for all peer-reviewed articles using keywords including "hamartoma of mature cardiac myocytes" from their inception to January 2nd, 2023.

RESULTS

We included 25 articles, including 34 cases, in this systematic review. Patients with hamartoma of mature cardiac myocytes commonly presented with nonspecific symptoms such as dyspnea (35.3%), although a few presented with sudden death and syncope. The left ventricle was the common site of origin (41.2%), followed by the right atrium and ventricle. Surgery was commonly pursued for diagnosis and treatment, while a few required cardiac transplants (8.8%), and 29.4% were diagnosed with autopsy or expired.

CONCLUSION

Hamartoma of mature cardiac myocytes is a potentially underrecognized primary cardiac tumor associated with treatable yet potentially critical consequences. Given the challenges of differentiating it from malignancy such as angiosarcoma, multimodal imaging needs to be utilized to pursue a diagnosis. Future studies are warranted to develop a noninvasive diagnosis mode for cardiac tumor.

A left atrial hamartoma of mature cardiac myocytes

We present a case of a hamartoma of mature cardiac myocytes. This is an extremely rare tumour and the first reported paediatric case localised in the left atrium.

Atypical Presentation of Right Ventricular Cardiac Hamartoma in a Young Man

Cardiac tumors in adults are exceedingly rare and usually benign. We describe a 29-year-old man with a previous diagnosis of interventricular septal hypertrophy who presented with increasing severity of dyspnea and fatigue. Work-up revealed a 4.9 × 3.7 cm mass at the base of the interventricular septum. Biopsy revealed a benign cardiac hamartoma atypically located in the right ventricle, and the mass was resected via right ventriculotomy.

Arrhythmogenic potential of myocardial disarray in hypertrophic cardiomyopathy: genetic basis, functional consequences and relation to sudden cardiac death

Myocardial disarray is defined as disorganized cardiomyocyte spatial distribution, with loss of physiological fibre alignment and orientation. Since the first pathological descriptions of hypertrophic cardiomyopathy (HCM), disarray appeared as a typical feature of this condition and sparked vivid debate regarding its specificity to the disease and clinical significance as a diagnostic marker and a risk factor for sudden death. Although much of the controversy surrounding its diagnostic value in HCM persists, it is increasingly recognized that myocardial disarray may be found in physiological contexts and in cardiac conditions different from HCM, raising the possibility that central focus should be placed on its quantity and distribution, rather than a mere presence. While further studies are needed to establish what amount of disarray should be considered as a hallmark of the disease, novel experimental approaches and emerging imaging techniques for the first time allow ex vivo and in vivo characterization of the myocardium to a molecular level. Such advances hold the promise of filling major gaps in our understanding of the functional consequences of myocardial disarray in HCM and specifically on arrhythmogenic propensity and as a risk factor for sudden death. Ultimately, these studies will clarify whether disarray represents a major determinant of the HCM clinical profile, and a potential therapeutic target, as opposed to an intriguing but largely innocent bystander.

A Rare Case of Cardiac Mesenchymal Hamartoma and Comprehensive Review of the Literature With Emphasis on Histopathology

Hamartomas are primary, benign neoplastic lesions that most commonly derive from a single variably differentiated cell lineage. Here, we report an unusual case of a cardiac hamartoma. A 62-year-old woman presented with chest pain and palpitations. Serial imaging revealed a large slowly growing and highly vascularized left ventricular mass, which required surgical resection. Microscopically, the lesion was composed of nodular fibrovascular proliferation with haphazardly embedded muscle bundles and peripheral calcifications. Immunohistochemical studies revealed prominent muscle-specific actin positive and smooth muscle actin positive muscle fiber bundles within a disorganized fibrovascular stroma. This characterization is most consistent with cardiac mesenchymal hamartoma. Relevant differential diagnoses for this lesion include hamartoma of mature cardiac myocytes (HMCMs) and intramuscular hemangioma. The prominent smooth muscle differentiation of muscle bundles was incompatible with defining features of HMCM. Absence of S100-positive nerve and mature adipose cells distinguished this lesion from the recently defined, heterogeneous cardiac mesenchymal hamartoma. Forty-seven cases of cardiac hamartoma reported from 1970 to 2020 were reviewed to provide histopathologic context.

Hamartoma of mature cardiomyocytes in right atrium: A case report and literature review

RATIONALE

Tumors in the heart are rare. Myxomas, rhabdomyomas, and fibromas are the most common benign cardiac tumors. Hamartoma of mature cardiomyocytes (HMCM) is another benign cardiac tumor, are very rare and have only been reported in a few literatures.

PATIENT CONCERNS

We report a case of 41-year-old male who suffered short of breath for 3 years, and lower limbs edema for 2 years.

DIAGNOSES

Transthoracic echocardiogram (TTE) and cardiac magnetic resonance (CMR) showed a large amount of pericardial effusion and confirmed a mass of 18 × 14 mm on the superior vena cava near the outer edge of right atrium. The patient was first diagnosed as pleural mesothelioma. Surgery was performed to relieve the symptoms and confirm diagnoses. However, during surgery, we found the right atrium is apparently thicken with rough and uneven surface. Histology of right atrium mass indicated it as hamartoma of mature cardiomyocytes.

INTERVENTION

We resected the thicken atrial wall completely, reconstructed right atrium with bovine pericardial patch, and resected the pericardium.

OUTCOMES

Patient was discharged 9 days after surgery, and remained asymptomatic during 9 months follow up.

LESSONS

Hamartoma of mature cardomyocytes is a rare benign cardiac tumor. There were 26 cases reported until now. The conclusive diagnosis depends on pathological sections. For patients with symptoms, surgery is an effective treatment for HMCM.

An unusual tumour: Hamartoma of mature cardiac myocytes

Heart neoplasms are uncommon and usually benign. Hamartoma of mature cardiac myocytes is an unusual lesion with only a few reported cases. It is a heterogeneous mixture of well-differentiated myocytes, fibroblasts, adipocytes and blood vessels. We present a case of hamartoma of mature cardiac myocytes and a concise review of the pertinent literature. A multi-lobulated polypoid tumour attached to the wall of the right atrium was found during an autopsy of a young woman. Microscopy revealed cardiomyocytes, fibrous connective tissue and well-differentiated adipocytes. The immunohistochemical study had a positive immunoreactivity for desmin, muscle-specific actin (HHF-35) and CD34 markers, showing the different types of mesenchymal cells involved. This combination of markers has not been previously used. Other tumours, such as cardiac rhabdomyoma and cardiac myxoma were ruled out due to the differences in histological characteristics and clinical presentation.

Hamartomas and other tumor-like malformations of the lungs and heart

Tumor-like malformative lesions are seen throughout the body, and they may be confused with true neoplasms by clinicians and pathologists alike. In the lungs, they are principally represented by hamartomas-which may contain chondroid, adipocytic, fibroblastic, and myxoid tissue, with entrapped bronchiolar epithelium-and congenital pulmonary airway malformations (CPAMs). The latter have been subdivided into 5 groups, based on their histological features, but they basically comprise proliferations of malformed bronchopulmonary tissues of different types. Type 1 lesions have a capacity for malignant transformation in a small proportion of cases. Malformative cardiac tumefactions include rhabdomyoma-like hamartomas; fibromatous hamartomas; and mesenchymal ventricular hamartomas, which contain cardiac muscle, smooth muscle, fat, vasogenic tissue, and nerves. Another intracardiac proliferation in the same general category is seen in the interatrial septum, in the region of the atrioventricular node. It comprises randomly-disposed gland-like profiles that are made up of endodermal epithelium. Originally thought to be a form of mesothelial lesion, that abnormality is now classified as an endodermal choristoma. All forms of pulmonary and cardiac malformations are only rarely symptomatic, and the necessity for surgical excision of them depends on the particular details of each case.

Cardiac Hamartoma: A Diagnostic Challenge

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Cardiac hamartoma is a rare clinical entity with hypertrophied myocytes mixed with fibro-vascular and fatty tissues.

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Multi-modality imaging is needed to narrow the differential diagnosis.

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Surgical resection can lead to the definitive diagnosis in some cases.

Cardiac Tumors

Cardiac neoplasms and other mass-forming lesions are not commonly encountered in surgical pathology practice. Fortunately, for the most part, these fall into a small group of well characterized and readily-recognized entities, although they are not without diagnostic dilemmas. A brief and practical synopsis of cardiac tumors is presented in this section with attention to more frequently encountered and clinically significant diagnostic challenges as well as pertinent clinical associations and prognostic information.

2011 consensus statement on endomyocardial biopsy from the Association for European Cardiovascular Pathology and the Society for Cardiovascular Pathology

The Association for European Cardiovascular Pathology and the Society for Cardiovascular Pathology have produced this position paper concerning the current role of endomyocardial biopsy (EMB) for the diagnosis of cardiac diseases and its contribution to patient management, focusing on pathological issues, with these aims: • Determining appropriate EMB use in the context of current diagnostic strategies for cardiac diseases and providing recommendations for its rational utilization • Providing standard criteria and guidance for appropriate tissue triage and pathological analysis • Promoting a team approach to EMB use, integrating the competences of pathologists, clinicians, and imagers.

Hamartoma of mature cardiac myocytes: case report and review of the literature

Cardiac hamartoma is an extremely rare type of benign cardiac tumour. A 35 year-old female presented with exertional dyspnea, palpitation, dry-cough and chest-tightness. A mass was discovered in the posterior-inferior wall of the left ventricle. A partial resection of the tumour was performed because of partial obstruction of the left ventricular inflow tract. Histological examination was indicative of a rare benign tumour of the heart: hamartoma of mature myocytes. A literature review completes the description.

Cardiac hamartoma in a young squirrel monkey who died suddenly

A case of cardiac hamartoma in a 2-month-old squirrel monkey is reported. The monkey showed a loss of appetite and died suddenly. Microscopically, an encapsulated nodular lesion was found at the right atrial wall. The lesion consisted of irregularly shaped, slender myocytes intermingled with a few fibroblasts and collagen fibers. Neither nuclear atypia nor inflammatory cell infiltrate was seen. The constituting cells had stratified striations in the cytoplasm and reacted immunohistochemically for desmin, indicating the nature of myocytes. Based on the above findings, a diagnosis of cardiac hamartoma was made. This is the first case of cardiac hamartoma in this species.

Cardiovascular pseudoneoplasms

CONTEXT

Primary cardiac tumors are rare and the great majority are benign neoplasms. Mass-forming reactive and pseudoneoplastic growths are less common, but recognizing and distinguishing these lesions from the neoplasms they resemble is critical to appropriate patient care.

OBJECTIVE

The general clinical, imaging, gross pathologic, and histologic features of 5 important pseudoneoplasms (inflammatory myofibroblastic tumor, hamartoma of mature cardiac myocytes, mesothelial/monocytic cardiac excrescences, calcified amorphous tumor, and lipomatous hypertrophy of the atrial septum) are discussed, with an emphasis on features differentiating them from other benign and malignant tumors.

DATA SOURCES

Pertinent citations of the literature and observations from the authors' experience are drawn upon.

CONCLUSIONS

While lacking malignant potential, these lesions can be associated with considerable morbidity and occasional mortality. Their recognition is important in guiding patient management, providing both guidance for appropriate therapy and avoidance of inappropriately aggressive and toxic treatments.

Heart transplantation for ventricular arrhythmia caused by a rare hamartoma

Hamartoma of mature cardiac myocytes is a form of cardiac tumor that shares some features with hypertrophic cardiomyopathy and rhabdomyomas. Here we describe a patient with a ventricular hamartoma complicated with ventricular tachycardia. Resection was not practical because of difficulty in maintaining the ventricular geometry, so heart transplantation was done.

Prenatal diagnsis of intracardiac hamartoma and Turner syndrome

Turner syndrome is associated with a higher frequency of heart defects detected prenatally when compared to postnatal reports. The most common heart defects detected prenatally are hypoplastic left heart syndrome and coarctation of the aorta. We report a case involving a fetus at 16 gestational weeks with a septated cystic hygroma located on the neck and head, an interventricular septal mass, a hypoplastic left ventricle due to aortic stenosis, mitral stenosis, and a hypoplastic aortic arch with a karyotype of mos 45, X, [47 cells]/47, XXX [3 cells]. The autopsy findings confirmed our prenatal diagnosis with a final diagnosis of Turner syndrome and congenital cardiac vascular malformation.

Giant right atrial cystic hamartoma: a case report and literature review

An 11-year-old boy presenting with palpitation and chest distress was found to have gross cardiomegaly on chest radiography. Subsequent echocardiography revealed an intramural giant cystic mass in the right atrium. An operative measure was planned to prevent acute cardiac tamponade and right coronary artery obstruction. The patient successfully underwent open cystectomy to remove the mass, which was located on the front wall of the right atrium and extended to the atrioventricular appendage. Histopathological examination confirmed a cystic hamartoma. To the best of our knowledge, this is the first reported case of a giant cystic hamartoma located on the right atrium.

TRIAL REGISTRATION NUMBER

704640.