Discussion
Primary cardiac tumors in childhood are extremely rare and detected tumors with a rate of 0.08% in autopsies, and are mostly benign. The most common histologically seen infantile cardiac tumors are rhabdomyoma (60% -85%) and according to their incidence, teratoma, fibroma, hemangioma and hamartomas, respectively. 4-6. In the last two decades, an increase in the incidence of pediatric cardiac tumors has been reported due to the increase in noninvasive imaging methods, the technological development of TTE devices and the widespread use of them. Patients admission complaints depend on the size and localization of the mass, as they have an inlet or outlet obstruction and arrhythmogenic effect 7. In general, the indications for resection are to eliminate hemodynamic and respiratory pathologies, if any, severe arrhythmia and a significant risk of embolization. These tumors are highly associated (60-80%) with TSC. It originates from the free wall of the ventricle and ventricular septum. The diagnosis of rhabdomyom is based on the characteristic TTE features of the tumor, in addition to the cutaneous, central nervous system or renal manifestations of tuberous sclerosis. In TTE examination, they are seen as well-circumscribed, homogeneous and echo bright masses. Many studies have shown that rhabdomyomas that are medically followed and partially resected will regress spontaneously within 1 to 3 years.
The patient we presented had AVSD and PDA accompanying rhabdomyoma. In the literature, the patient with congenital heart defect associated with TS and rhabdomyom is very rare. In the study published by Jiang et al.3, they mentioned that the heart may disrupt the growth pattern in the region where the mass appeared during the embryological development phase. In our case, since the intrauterine cardiac examination was not performed, it cannot be clearly revealed in which trimester the rhabdomyoma occurred. However, the atrioventricular canal defect and the area where the rhabdomyom is located are very close, suggesting that the tumor may have caused the supposed development defect.
In the literature, it has been observed that the rhabdomyoma associated with the TSC is largely multiple. However, we observed a solitary rhabdomyom in our case. In the study conducted by Bader et al. with 26 patients, the tumors in diagnosis were single in 5 patients (19%) including right or left ventricle and multiple in 21 patients (80.8%)8. In a study conducted by Sciacca et al. with 33 patients, multiple rhabdomyomas were detected in all tuberous sclerosis patients 9. It is well known that AV channel defects often coexist with down syndrome. However, in our case, the absence of down syndrome is also interesting.
We did not excise rhabdomyoma in our patient, since it was asymptomatic, was largely intramyocardial, and would cause destruction in the surrounding structures during excision. Malign arrhythmias that may develop in the postoperative period after excision could be fatal. After birth, rhabdomioma cells lose their ability to divide, and tumor regression in infancy is an expected result regardless of tumor size. In more than 80% of tumors, full regression can occur in early childhood. In addition, it has been revealed by many studies everolimus, an mTOR inhibitor, have shown that this drug accelerates shrinkage in the size of rhabdomiomas by up to 12 times 10,11.