These cases illustrate that it is very difficult to differentiate giant cell myocarditis (inflammation of the muscular substance of the heart) from sarcoidosis (chronic disease of unknown cause characterized by the development of lesions in the lungs, bones, skin, etc.) on the basis of clinical history and morphologic examination alone. In one of the presented cases, this differentiation was made based on the involvement of the lungs and lymph nodes, which is characteristic of sarcoidosis. In the second case, the differentiation was made by the localization of the granulomatous process to the myocardium, which led to the diagnosis of giant cell myocarditis. These findings support those of Rashid and Williams, indicating that thorough gross and microscopic examinations of other organs and lymph nodes are required to exclude a diagnosis of sarcoidosis in sudden cardiac death due to giant cell inflammatory processes. In the first case, an 18-year-old Hispanic man was found collapsed in a shower stall at a job site where he had been laying tile. He was pronounced dead at the scene. His medical history showed no previous problems other than his complaints of vague abdominal pain for approximately 2 1/2 months prior to his death. In the second case, a 43-year-old White man collapsed at work after complaining to coworkers of dizziness. Cardiopulmonary resuscitation was unsuccessful, and he was pronounced dead in the emergency room at a local hospital. His past medical history showed an episode approximately 10 years earlier, when he awoke with a sensation of pressure in his chest. 9 figures and 53 references