Cardiac sarcoidosis with severe involvement of the right ventricle: a case report

We present the case of a patient who underwent cardiac transplantation with the diagnosis of idiopathic dilated cardiomyopathy. Once the explanted heart was examined, a type of granulomatous myocarditis compatible with cardiac sarcoidosis was observed. However, there was severe involvement of the right ventricle, with markedly reduced width of the muscular layer and extensive fibrofatty replacement, findings similar to the ones encountered in cases of arrhythmogenic right ventricular cardiomyopathy (ARVC). Confocal immunofluorescence analysis revealed a reduced signal for plakoglobin and desmoplakin at the cardiac intercalated disks. The immunoreactive signal for desmin showed the typical sarcomeric distribution but not a concentrated signal at the intercalated disks, a pattern previously seen in an 11-year-old girl with Carvajal syndrome bearing a C-terminal truncating mutation in the desmoplakin gene. This case illustrates the difficult and challenging work involved in performing a differential diagnosis among idiopathic dilated cardiomyopathy, isolated cardiac sarcoidosis, and ARVC, all of which are clinical entities known to masquerade as one another.