Left ventricular mesenchymal hamartoma, a new hamartoma of the heart

Cardiac Tumors Causing Sudden Cardiac Death: A State-of-the-Art Review in Pathology

Cardiac tumors (CTs), although rare, can be a significant cause of sudden cardiac death (SCD), particularly when not diagnosed early. The tumors most associated with SCD include myxomas, fibromas, rhabdomyomas, and sarcomas, which can cause fatal arrhythmias, blood flow obstruction, or embolization. Myxomas, which often develop in the left atrium, can cause valvular obstruction or cerebral emboli, while malignant tumors, such as sarcomas, can infiltrate the myocardium or conduction system, causing serious arrhythmias. Rhabdomyomas, which are common in children and associated with tuberous sclerosis, can lead to ventricular tachyarrhythmias. Early diagnosis using advanced imaging techniques such as echocardiography and magnetic resonance imaging is crucial for preventing SCD. Timely diagnosis and precise characterization of lesions can help reduce the risk of SCD, thus improving the clinical management of patients, with the aim of supporting personalized treatment and improving life prospects. In this state-of-the-art review, we analyze the association between CTs and SCD, with particular attention to the histological features of benign and malignant neoplasms. Through an updated overview of the pathological aspects, we aim to improve the understanding of these tumors and promote a more effective multidisciplinary diagnostic and therapeutic approach to prevent fatal events.

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.

A Case of Ventricular Tachycardia Caused by a Rare Cardiac Mesenchymal Hamartoma

The presentation of a cardiac hamartoma, an exceedingly rare and histologically benign cardiac tumor, can be variable. We describe a case of refractory ventricular tachycardia in a patient with a cardiac mass failing multiple pharmacologic and procedural interventions, ultimately treated by cardiac transplantation and diagnosed with a mesenchymal cardiac hamartoma. (Level of Difficulty: Intermediate.).

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.

The 2015 WHO Classification of Tumors of the Heart and Pericardium

This article reviews the nomenclature of benign and malignant neoplasm of the heart and pericardium in the 4th edition of the World Health Organization's Classification, with emphasis on differences since the 3rd edition of 2004. The tumours are divided into benign, malignant, and intermediate tumors of uncertain behavior, with separate sections on germ cell tumours and tumors of the pericardium. There are important updates in the sarcoma classification, with emphasis on the most common site, the left atrium. The importance of the new genetic finding in cardiac myxomas, namely somatic mutations in the PRKAR1A gene underscores the importance of this alteration in the pathogenesis of these tumors. Challenges on the classification of each entity are discussed.