Multiple cardiac rhabdomyomas not associated with tuberous sclerosis in a dizygotic twins: a case report

BACKGROUND: Rhabdomyomas comprise the majority of cardiac tumors in fetuses and are found in association with tuberous sclerosis complex. More than 90% of fetuses and neonates with multiple cardiac rhabdomyomas have signs of tuberous sclerosis complex. However, solitary cardiac rhabdomyoma cases are largely unrelated to tuberous sclerosis complex. Here, we report a case involving multiple cardiac rhabdomyomas not associated with tuberous sclerosis complex in a dizygotic twin. CASE PRESENTATION: A 36-year-old Japanese woman was diagnosed with a dizygotic twin pregnancy in the first trimester. Consistent with dizygosity, the fetal sex was discordant (male and female). At 27 weeks of gestation, hydrops and multiple echogenic cardiac masses were noted in the male baby, with the largest mass measuring 34 × 30 mm. The female fetus appeared normal. The cardiac masses enlarged gradually with the progression of the hydrops. At 32 weeks of gestation, intrauterine death of the male fetus was confirmed. The next day, autopsy of the male fetus was performed after cesarean section. Three well-demarcated white-tan-colored nodules were formed in the ventricular walls and interventricular septum, with the largest nodule (40 × 30 mm) in the left ventricular wall. Histologically, these lesions were diagnosed as rhabdomyomas. CONCLUSIONS: We encountered a case involving multiple cardiac rhabdomyomas arising in one of dizygotic twin fetuses. Unlike most reported cases of multiple cardiac rhabdomyomas, this case was not accompanied by tuberous sclerosis complex. To the best of our knowledge, this is the first case report of multiple cardiac rhabdomyomas that developed in only one of dizygotic twins in the English literature.