Key histologic findings of ARVC in sections taken from the right ventricle:
(1) full thickness or almost full thickness fibrofatty infiltration of the right ventricle
(2) small islands with a thin rim of lamellar fibrosis encasing a few myocardial fibers
Pathologic features that should cause the pathologist to consider the diagnosis of ARVC:
(1) dilatation of right ventricle
(1a) with or without dilatation of the left ventricle
(1b) with or without wall thinning
(1c) with or without aneurysm formation
(2) fibrofatty infiltration of the left ventricle with lamellar fibrosis
(3) restricted right-sided septal fibrosis
(4) multiple, subtle foci of myocarditis scattered in different compartments of the heart
(5) fibrofatty infiltration of the trabeculae carneae
Conditions that can cause changes that may mimic ARVC:
(1) coronary artery disease
(2) severe valvular disease other than mitral valve prolapse
