Myocarditis: Pathologist's perspective

Myocarditis is a challenging diagnosis for both clinician and pathologist due to the extreme diversity of clinical presentation and low sensitivity of detection of myocarditis in the endomyocardial samples. The exact incidence of myocarditis is still not known as endomyocardial biopsy (EMB) is not performed in all suspected cases of myocarditis in majority of the centers. Identification of Dallas criteria in EMB is still considered as a gold standard in the diagnosis of myocarditis. Viral myocarditis is one of the most common causes of myocarditis next to idiopathic or primary myocarditis. Virtually any type of virus can affect the heart. Idiopathic myocarditis should be categorized depending upon the histopathological findings and clinical features as fulminant, chronic active, eosinophilic, granulomatous, or giant cell myocarditis. Hence, a thorough basic set of all relevant investigations including molecular study should be carried out in the evaluation of clinically suspected viral myocarditis patients to identify the active phase of the viral disease process which ultimately helps in the determination of treatment protocol and prognosis