Arrhythmogenic cardiomyopathy (AC) has traditionally been regarded as a rare disease with variably penetrant autosomal-dominant inheritance. Recent years have revealed that AC is actually a spectrum of disease with prevalence much higher than previously thought. Diagnosis can be quite challenging because of highly variable clinical presentation, even among family members sharing a mutation. Unlike other cardiomyopathies, AC has a concealed phase during which patients have arrhythmias in the absence of structural heart disease but remain at risk of sudden cardiac death. Importantly, it is in the setting of sudden cardiac death that pathologists are most likely to encounter AC. It is critical that these findings not be overlooked, as family members of the deceased may also be affected and could potentially avoid such a dismal outcome. With time, advances in ancillary studies are likely to expand the role for pathologists in AC diagnosis.