Comparison of certain clinical and pathologic features among patients who have nonfamilial cardiac myxoma with those of patients who have familial cardiac myxoma showed statistically significant differences. Nonfamilial cardiac myxoma was a disorder of middle-aged (mean age, 51 years) women (76%), usually occurred in the left atrium (86%) as a single tumor (94%), and had no particular associated conditions. Familial cardiac myxoma, on the other hand, was a disorder of young (mean age, 24 years) men (66%), was less commonly in the left atrium (62%), was often multicentric (33%), and was occasionally associated with unusual or rare conditions (20%).