This endomyocardial biopsy discloses a marked infiltrate of chronic inflammatory cells including lymphocytes, histiocytes, and eosinophils. Focally, the histiocytes appear to aggregate in poorly formed granulomas. Scattered multinucleated giant cells are present, some of which appear to be histiocytic and some of which appear to be muscle giant cells. This infiltrate does not have the typical appearance of sarcoidosis. No microorganisms or viral inclusions are identified. These changes are consistent with a diagnosis of giant cell myocarditis.
GIANT CELL MYOCARDITIS
- Giant cell myocarditis is a rare and highly lethal disorder that was first described by Saltykow in 1905
- Less than 300 cases have been reported in sub-sequent years
- All GCM cases were either fatal or were managed with heart transplantation until 1987, when the successful treatment of GCM with triple drug immune suppression was reported
- Autopsy studies conducted a number of years ago in England and Japan reported the incidence of GCM as 23.4 per 100,000 and 6.6 per 100,000
- GCM and cardiac sarcoidosis were historically grouped together. They have different clinical and histologic features
- CS specimens had significantly more granulomas and fibrosis, while GCM had more necrosis and eosinophils
- GCM is usually an acute disease with rapid deterioration over weeks, while CS progresses over months to years
- Endomyocardial biopsy (EMB) should be considered in younger patients with idiopathic complete heart block to diagnose GCM or CS especially if a cardiomyopathy is present
- About MRI: “…not a perfect alternative because CMR information is less detailed and—in contrast to biopsy—does not allow to evaluate the exact degree of inflammation, the presence of special forms of myocarditis (such as giant cell or eosinophilic myocarditis which require specific therapies), or the presence and type of virus”
References:
- Blauwet LA, Cooper LT. Idiopathic giant cell myocarditis and cardiac sarcoidosis. Heart Fail Rev. 2012 Oct 31.
- Yilmaz A, Ferreira V, Klingel K, Kandolf R, Neubauer S, Sechtem U. Role of cardiovascular magnetic resonance imaging (CMR) in the diagnosis of acute and chronic myocarditis. Heart Fail Rev. 2012 Oct 18.
- Cooper LT Jr, ElAmm C. Giant cell myocarditis. Diagnosis and treatment. Herz. 2012 Sep;37(6):632-6.
Case is courtesy of Travis S. Henry, MD.