Deoxyribonucleic acid ploidy pattern of cardiac myxomas. Another predictor of biologically unusual myxomas.

A group of patients with cardiac myxoma who have a heritable syndrome involving skin myxomas, endocrine tumors, and lentiginosis--the complex of myxomas, spotty pigmentation, and endocrine overactivity--has been described previously. Patients with the complex had cardiac myxomas at an early age (average, 26 years) with frequent multiple myxomas (53%) and recurrent cardiac myxomas (22%); however, no histologic differences were noted when these tumors were compared with sporadic cardiac myxomas. In the present study, deoxyribonucleic acid flow cytometric analyses of 35 cardiac myxoma specimens were correlated with clinical findings (mean duration of follow-up, 13 years). Among 30 patients with sporadic (nonfamilial) cardiac myxoma, 24 (80%) had a normal (deoxyribonucleic acid diploid) ploidy pattern, and six (20%) had an abnormal (deoxyribonucleic acid tetraploid) pattern. Specimens from each of the five patients with the complex had abnormal deoxyribonucleic acid tetraploid patterns (p = 0.002 compared with the sporadic myxoma group). Further, all four patients who had recurrent cardiac myxoma had an abnormal deoxyribonucleic acid ploidy pattern (p = 0.007 compared with patients with nonrecurrent myxomas). Unlike conventional histologic examination, the ploidy pattern of cardiac myxomas seems to be sensitive for detecting biologically unusual tumors, and a deoxyribonucleic acid tetraploid pattern suggests a high risk of recurrence.