Ventricular septal hamartoma mimicking hypertrophic cardiomyopathy in a 41-year-old woman presenting with paroxysmal supraventricular tachycardia

Left Ventricular Outflow Tract Obstruction Due to Cardiac Hamartoma

Hamartoma of mature cardiac myocytes (HMCM) is a rare, benign cardiac tumor. We report a case of a 19-year-old female with an atypical presentation, including significant weight loss and abnormal electrocardiogram. A transthoracic echocardiogram (TTE) revealed a mass causing left ventricular outflow tract (LVOT) obstruction, confirmed by cardiac magnetic resonance (CMR) imaging showing a 5 x 3 cm mass contiguous with the right ventricular free wall and exhibiting heterogeneous, diffuse late gadolinium enhancement. The patient subsequently underwent sternotomy for surgical biopsy and septal myectomy, with histology of the mass being consistent with HMCM. The patient remained asymptomatic during her 6-month follow-up.

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.

Tumoral Phenocopies of Hypertrophic Cardiomyopathy: The Role of Cardiac Magnetic Resonance

Hypertrophic cardiomyopathy (HCM) is a genetic cardiac disease that presents with cardiac hypertrophy. HCM phenocopies are clinical conditions that are phenotypically undistinguishable from HCM, but with a different underlying etiology. Cardiac tumors are rare entities that can sometimes mimic HCM in their echocardiographic appearance, thus representing an example of HCM phenocopy. At present, only case reports of tumoral HCM phenocopies can be found in literature. In this systematic review, we analyzed all the published cases in which a cardiac tumor mimicked HCM to the point of misleading the diagnosis, providing a structured overview of the currently available evidence on this topic.

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.

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.

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.