A clinical case of a 10-year-old male patient is reported. His dilated and prevailing right ventricular myocardiopathy shows diagnostic difficulties between previous myocarditis etiology and arrhythmogenic dysplasia. As the elements are not pathognomonic of one or other cause, the increase of cardiac enzymes in subacute stage maybe tends to the supposition of previous myocarditis. Hence, the questioning that many cases labeled as arrhythmogenic dysplasia can truly correspond to the possibility of evolutional myocarditis. The controversial clinic management is disputable.