Regression of Neonatal Cardiac Rhabdomyoma in Two Months Through Low-Dose Everolimus Therapy: A Report of Three Cases

Cardiac Rhabdomyomas Presenting with Critical Cardiac Obstruction in Neonates and Infants: Treatment Strategies and Outcome, A Single-Center Experience

Cardiac rhabdomyomas are the most common benign pediatric heart tumor in infancy, which are commonly associated with tuberous sclerosis complex (TSC). Most rhabdomyomas are asymptomatic and spontaneously regress over time. However, some cases especially in neonates or small infants can present with hemodynamic instability. Surgical resection of the tumor, which has been the gold standard in alleviating obstruction, is not always possible and may be associated with significant morbidity and mortality. Recently, mammalian target of rapamycin inhibitors (mTORi) have been shown to be safe and effective in the treatment of TSC. We present the outcomes of neonates and an infant who received treatment for symptomatic rhabdomyomas at a tertiary cardiology center. Medical records were reviewed to obtain clinical, demographic, and outcome data. Six patients received interventions for symptomatic rhabdomyomas, median age at presentation was 1 day old (range from 1 to 121 days old), and 67% of the patients had a pathogenic mutation in TSC gene. One patient underwent surgical resection of solitary tumor at right ventricular outflow tract (RVOT) successfully. In the four patients with left ventricular outflow tract (LVOT) obstruction, two patients received combined therapy of surgical debulking of LVOT tumor, Stage I palliation procedure, and mTORi and two patients received mTORi therapy. One patient with RVOT obstruction underwent ductal stenting and received synergistic mTORi. Four of the five patients had good response to mTORi demonstrated by the rapid regression of rhabdomyoma size. 83% of patients are still alive at their latest follow-up, at two to eight years of age. One patient died on day 17 post-LVOT tumor resection and Hybrid stage one due to failure of hemostasis, in the background of familial factor VII deficiency. Treatment of symptomatic rhabdomyoma requires individualized treatment strategy based on the underlying pathophysiology, with involvement of multidisciplinary teams. mTORi is effective and safe in inducing rapid regression of rhabdomyomas. A standardized mTORi prescription and monitoring guide will ensure medication safety in neonates and infants with symptomatic cardiac rhabdomyoma. Although the majority of tumors responded to mTORi, some prove to be resistant. Further studies are warranted, ideally involving multiple international centers with a larger number of patients.

Three-Year Follow-Up after Intrauterine mTOR Inhibitor Administration for Fetus with TSC-Associated Rhabdomyoma

Tuberous sclerosis complex (TSC) is a multisystem disorder characterized by seizures, neuropsychiatric disorders, and tumors of the heart, brain, skin, lungs, and kidneys. We present a three-year follow-up of a patient with TSC-associated rhabdomyoma detected in utero. Genetic examination of the fetus and the parents revealed a de novo variant in the TSC2 gene (c.3037delG, p.Asp1013IlefsTer3). Oral everolimus was initiated in the pregnant mother to regress the fetal tumor, which was successful. To the best of our knowledge, there is very little information regarding the use of everolimus therapy during pregnancy. West-syndrome was diagnosed when the proband was four months old. The symptoms were well-manageable, however temporarily. Therapy-resistant focal seizures were frequent. The patient had good vitals and was under regular cardiological control, showed a balanced circulation, and did not require any medication. Subependymal giant cell astrocytoma (SEGA) identified by regular neuroimaging examinations remained unchanged, which may be a consequence of early intrauterine treatment. Early detection of the pathogenic TSC2 variant, followed by in utero administration of everolimus and early vigabatrin therapy, allowed the detection of a milder developmental delay of the proband. Our study emphasizes how early genetic testing and management of epilepsy are pivotal for proper neurodevelopmental impacts and therapeutic strategies.

Current status of diagnosis and treatment of primary benign cardiac tumors in children

Primary cardiac tumors in children are exceedingly rare overall, which benign account for most part. The onset of the disease is occult, while the clinical manifestations are non-specific-patients may be asymptomatic or show a range of obstructive, arrhythmic, embolic or systemic symptoms. The clinical presentations generally depend on the tumors’ size, localization, and pace of growth of the tumor. Moreover, the diagnosis needs comprehensive judgment based on imaging results and pathological examination. With advances in cardiac imagining and the introduction of cardiopulmonary support, the diagnosis and treatment of these rare tumors have improved the prognosis and outlook for benign tumors. To sum up the above, we sought to integrate articles from recent years for the latest comprehensive review of the clinical manifestations, imaging characteristics, clinic pathologic features and treatment of benign cardiac tumors in children to provide a broader idea for pediatricians to recognize and treat such diseases.

Findings and Outcome of Transcatheter Right Ventricular Endomyocardial Biopsy and Hemodynamic Assessment in Children with Suspected Myocarditis or Cardiomyopathy

OBJECTIVE

The study objective is assessing findings and outcome in children with suspected cardiomyopathy (CMP) or myocarditis undergoing cardiac catheterization with transcatheter right ventricular endomyocardial biopsy (RV-EMB).

METHODS

All consecutive children undergoing cardiac catheterization with RV-EMB for suspected CMP/myocarditis between 2002-2021 were analysed regarding clinical presentation, cardiac biomarkers, periprocedural management, hemodynamic, histological/immunohistological findings, and outcome.

RESULTS

Eighty-five RV-EMBs were performed in 81 patients at a median age of 6.8 (IQR 9.9) years and a bodyweight of 20 (32.2) kg. Histological/immunohistological findings of RV-EMB revealed dilated CMP in 10 (12%), chronic myocarditis in 28 (33%), healing myocarditis in 5 (6%), acute myocarditis in 9 (11%), other heart muscle diseases in 23 (27%) (7 restrictive CMP, 5 hypertrophic CMP, 4 toxic/anthracycline-induced CMP, 4 endocardfibroelastosis, 1 arrhythmogenic right ventricular CMP, 1 laminin CMP, 1 haemangioma), no conclusive histology in 7 (8%), and normal histology in 3 (4%) patients. Median LVEDP was 17 mmHg (IQR 9), LAP 15 mmHg (10), and PVR 1.83 (1.87) Wood Units/m². There were 3 major complications (3%), all patients recovered without any sequelae. At follow-up (median 1153, IQR 1799 days) 47 (59%) patients were alive, 11 (13%) dead, 15 (18%) underwent cardiac transplantation, and 8 (9%) were lost to follow-up. Death/cardiac transplantation occurred within 3 years from RV-EMB. All patients with an acute myocarditis survived. NT-pro-BNP, echo parameters, and invasive hemodynamics correlate independently with death/cardiac transplant.

CONCLUSION

Hemodynamic invasive data and morphological findings in RV-EMB complete clinical diagnosis in children with suspected CMP/myocarditis and provide important information for further clinical management.

Efficacy of Everolimus Low-Dose Treatment for Cardiac Rhabdomyomas in Neonatal Tuberous Sclerosis: Case Report and Literature Review

Background: Cardiac rhabdomyomas (CRs) are the most common cardiac tumors in newborns. Approximately 80-90% of cases are associated with tuberous sclerosis complex (TSC). In selective cases, Everolimus has resulted in a remarkable tumoral regression effect in children with TS. The optimal dosage for neonates is still unknown. Case presentation: We describe the use of Everolimus in a neonate with multiple biventricular CRs, causing subaortic obstruction, in which a low-dose treatment (0.1 mg/die), in an effort to maintain serum trough levels of 3-7 ng/mL, was successfully used off-label, without adverse effects. Conclusions: We showed that a low-dose Everolimus regimen may be an effective and safe treatment for CR regression in TS neonates, when the minimum therapeutic range was maintained.

Everolimus for severe arrhythmias in tuberous sclerosis complex related cardiac rhabdomyomas

Intracardiac rhabdomyoma is the most common primary cardiac tumor in children. Most cases are associated with tuberous sclerosis complex (TSC). Most of them are asymptomatic in the neonate and do not require treatment. However, some develop cardiovascular symptoms such as arrhythmias, heart failure, and ventricular inflow/outflow tract obstruction in the neonatal period with early death. Many of these tumors are not candidates for surgical resection and medical management is limited. Treatment with mammalian target of rapamycin (mTOR) inhibitor is currently approved for the management of central nervous tumors and angiomyolipoma in TSC. Two patients with malignant arrhythmias related to nonsurgical multiple rhabdomyomas associated with TSC who were successfully treated with an mTOR inhibitor were described. Everolimus therapy showed significant regression of rhabdomyomas with rapid improvement of arrhythmias and heart failure prior to tumor shrinkage.

Combination percutaneous and medical management of cardiac rhabdomyomas obstructing tricuspid valve inflow: Case report

BACKGROUND

Cardiac rhabdomyomas can be prenatally diagnosed in patients with tuberous sclerosis complex. Many neonates require no intervention in early life other than close monitoring for regression of tumor over the period of months to years. In rare instances, cardiac rhabdomyomas can result in obstruction to blood flow or decreased ventricular function.

CASE REPORT

We describe the case of a neonate who was prenatally diagnosed with multiple large cardiac rhabdomyomas, one of which caused clinically significant obstruction to prograde blood flow across the tricuspid valve in the newborn period. To address the disturbance to prograde pulmonary blood flow, the patient underwent successful ductal stent placement in the neonatal period. A troponin elevation was noted shortly after birth, but no evidence of coronary compression or involvement was demonstrated by coronary angiography. The patient has subsequently been treated with sirolimus over a period of three months, with noted regression in tumors and improvement in tricuspid valve inflow.

CONCLUSIONS

A brief review of the literature regarding the diagnosis, treatment, and management of neonatal patients with cardiac rhabdomyomas is presented. A combined percutaneous and medical management approach may be of benefit in future cases of rhabdomyomas causing obstruction to pulmonary blood flow.

Rapid response of a cardiac rhabdomyoma causing severe right ventricular outflow obstruction to Sirolimus in an infant with negative genetics for Tuberous sclerosis

Mammalian target of rapamycin inhibitors was found recently to be an effective treatment for manifestations of Tuberous sclerosis complex, including cardiac rhabdomyomas. Most cases with Cardiac rhabdomyoma treated with mammalian target of rapamycin inhibitors to date were diagnosed with Tuberous sclerosis. We report a case of cardiac rhabdomyoma and severe right ventricular outflow obstruction in a baby with negative genetics for Tuberous sclerosis that responded rapidly to Sirolimus.

Efficacy and safety of low-dose everolimus treatment for renal angiomyolipoma associated with tuberous sclerosis complex

BACKGROUND

The aim of this study was to evaluate the safety and efficacy of low-dose everolimus treatment in patients with tuberous sclerosis complex (TSC)-associated angiomyolipoma (AML) with renal dysfunction or low body weight.

METHODS

We investigated a total of 50 adult patients underwent everolimus treatment for AML associated with TSC. For patients with renal dysfunction (serum creatinine level ≥ 1.5 mg/dl) or low body weight (body weight < 35 kg), 5 mg of everolimus was administered daily (low-dose group). For patients without renal dysfunction or low body weight, 10 mg of everolimus was administered daily (conventional-dose group). The treatment effects and adverse events were compared between the two groups.

RESULTS

There were 20 patients in the low-dose group, and 30 in the conventional-dose group. The average reduction rate of the AML volume in the low-dose group was 52%, whereas it was 60% in the conventional-dose group. No significant differences were found in the average reduction rate between the groups (P = 0.24). The average blood everolimus trough levels were 7.7 ± 3.1 ng/mL in the low-dose group and 12.2 ± 5.7 ng/mL in the conventional-dose group. The level was significantly higher in the conventional-dose group than in the low-dose group (P = 0.004). The incidences of stomatitis and irregular menstruation were significantly lower in the low-dose group than in the conventional-dose group (P = 0.009, P = 0.045, respectively).

CONCLUSIONS

The present study demonstrates that low-dose everolimus treatment is safe and effective for TSC-associated AML. This treatment was well tolerated and adverse events were mild in all cases.

Echocardiography and Newer Imaging Techniques in Diagnosis and Long-Term Follow-Up of Primary Heart Tumors in Children

Background: Primary heart tumors (PHTs) in the pediatric population are very rare and do not manifest any characteristic symptoms. Methods: A retrospective analysis of 61 cases was undertaken. Data from three centers for the years 2003–2018 were gathered. The tumors’ clinical course, location, number, hemodynamic, treatment, and follow-up were evaluated. Echocardiography was complemented with magnetic resonance imaging, computer tomography, and histopathological examination. Results: Out of 61 PHT diagnoses, 56 (91.8%) were circumstantial including all 16 (26.2%) prenatal tumors. The reasons for cardiological consultations were arrhythmia, syncopes, lowered physical performance, and murmurs. Only five patients (8.2%) were suspected of tumors based on previous symptoms of sclerosis tuberosa. Rhabdomyoma was the most frequently found PHT (60.7%). The tumors were predominantly located in the ventricles (49.1%) and intraventricular septum (14.9%) and tended to be single (70.5%). About 37.7% of patients suffered from coexistent multi-organ problems, two (3.28%) from congenital heart defects and one (1.64%) from Carney’s syndrome. Tumor resection was performed on 26 (42.7%) patients, of which 16 (61.5%) underwent total and 10 (38.5%) partial tumor resection. During the follow-up (mean 4.3 years), 54 patients (88.5%) have improved or were stable, while seven (11.5%) died. Conclusions: Primary pediatric heart tumors are diagnosed completely circumstantially, and the most common is rhabdomyoma, although arrhythmia may suggest fibroma. Diagnosis of a heart tumor in children is not synonymous with fatal prognosis, and most of them require only constant observation. Life-saving operation allows improvement, while the prognosis for malignant tumors in children is definitely unfavorable.

Literature review of international mammalian target of rapamycin inhibitor use in the non-surgical management of haemodynamically significant cardiac rhabdomyomas

Cardiac rhabdomyomas represent the most common primary paediatric cardiac tumour and typically regresses over time in the majority of patients. Among those who are symptomatic, surgical resection or catheterisation procedures have traditionally proven effective. More recently, those invasive or challenging tumours have been successfully treated with mammalian target of rapamycin inhibitors, typically everolimus and sirolimus. This review outlines the current medical literature of the state-of-the-art medical treatment of these tumours. We specifically focus on dosing regimens, duration of therapy, and side-effect profiles of mammalian target of rapamycin inhibitors among this population. Although the majority of cases responded to mammalian target of rapamycin inhibition, standardised guidelines for dosing and duration of treatment remain to be defined.

A case of surgically resected cardiac rhabdomyoma with progressive left ventricular outflow tract obstruction

Cardiac rhabdomyoma is the most prevalent cardiac tumors in the pediatric population, in close association with tuberous sclerosis complex. It is usually detected antenatally or postnatally by echocardiography. Clinical presentations depend greatly on the size and position of the tumor mass. Interestingly, rhabdomyoma has a propensity to regress spontaneously and is not usually operated upon, unless the patient becomes hemodynamically compromised. Herein, we report an unusual case of surgically treated cardiac rhabdomyoma in a baby boy presented at birth with a progressive enlarging intraventricular mass, complicated with left ventricular outflow tract obstruction 7 weeks later. Histopathological examination of the intracardiac mass revealed sheets of tumor cells with spider-like morphology (known as "spider cells"), confirmed the diagnosis of rhabdomyoma. Close disease monitoring of patient's hemodynamic status in a newly diagnosed cardiac rhabdomyoma is inevitable as the tumor, although rare, may progress.

Solitary neurofibroma of the heart

Solitary neurofibroma of the heart is extremely unusual. Few reports of neurofibroma in the left ventricle have been published. In this case report, we present the results of transthoracic echocardiography, myocardial contrast echocardiography, cardiac magnetic resonance imaging, and histopathologic examination of a patient with a neurofibroma of the heart. The patient had no evidence of any other metastasis or primary tumor in other organs, which is clinically rare.

Everolimus for cardiac rhabdomyomas in children with tuberous sclerosis. The ORACLE study protocol (everOlimus for caRdiac rhAbdomyomas in tuberous sCLErosis): a randomised, multicentre, placebo-controlled, double-blind phase II trial

INTRODUCTION

Tuberous sclerosis complex is a rare genetic disorder leading to the growth of hamartomas in multiple organs, including cardiac rhabdomyomas. Children with symptomatic cardiac rhabdomyoma require frequent admissions to intensive care units, have major complications, namely, arrhythmias, cardiac outflow tract obstruction and heart failure, affecting the quality of life and taking on high healthcare cost. Currently, there is no standard pharmacological treatment for this condition, and the management includes a conservative approach and supportive care. Everolimus has shown positive effects on subependymal giant cell astrocytomas, renal angiomyolipoma and refractory seizures associated with tuberous sclerosis complex. However, evidence supporting efficacy in symptomatic cardiac rhabdomyoma is limited to case reports. The ORACLE trial is the first randomised clinical trial assessing the efficacy of everolimus as a specific therapy for symptomatic cardiac rhabdomyoma.

METHODS

ORACLE is a phase II, prospective, randomised, placebo-controlled, double-blind, multicentre protocol trial. A total of 40 children with symptomatic cardiac rhabdomyoma secondary to tuberous sclerosis complex will be randomised to receive oral everolimus or placebo for 3 months. The primary outcome is 50% or more reduction in the tumour size related to baseline. As secondary outcomes we include the presence of arrhythmias, pericardial effusion, intracardiac obstruction, adverse events, progression of tumour reduction and effect on heart failure.

CONCLUSIONS

ORACLE protocol addresses a relevant unmet need in children with tuberous sclerosis complex and cardiac rhabdomyoma. The results of the trial will potentially support the first evidence-based therapy for this condition.

Use of Cardiac MRI to Assess Antitumor Efficacy of Everolimus in Sporadic Cardiac Rhabdomyoma

Cardiac rhabdomyoma is the most common neonatal cardiac tumor and is typically associated with tuberous sclerosis complex (TSC). Although these tumors may naturally regress, some patients require surgical resection because of cardiac instability. If not fully resected, patients may also require medical therapy to improve their hemodynamics. Everolimus, a mammalian target of rapamycin inhibitor, has shown promise in reducing rhabdomyoma in patients with TSC, but the drug's impact in patients without TSC has not been reported. Monitoring of tumor response has typically been limited to echocardiograms, which is not ideal given inherent difficulties in three-dimensional measurements. We report a case of sporadic cardiac rhabdomyoma in a neonate treated with everolimus resulting in tumor regression as documented by cardiac MRI. While on everolimus, our patient had an increased incidence of a preexisting arrhythmia, which resolved with planned cessation of therapy, suggesting that close monitoring is imperative in patients with arrhythmia.

Rapid Involution of Large Cardiac Rhabdomyomas With Everolimus Therapy

Rhabdomyoma of the fetal heart is a rare disease accounting for about 1% of all fetal cardiac structural anomalies. They are often found in association with tuberous sclerosis complex. Large cardiac rhabdomyomas can compromise the cardiac function. We report a case of multiple large rhabdomyomas of the right and left ventricles, affecting the cardiac function, which was successfully treated with the chemotherapeutic and immunosuppressive medication everolimus, in a neonate with genetically confirmed tuberous sclerosis complex with multisystem manifestations. There was rapid involution of the tumors in response to everolimus therapy in this infant.

Safety and efficacy of mTOR inhibitor treatment in patients with tuberous sclerosis complex under 2 years of age - a multicenter retrospective study

Background

Tuberous sclerosis complex (TSC) is a multisystem disease with prominent neurologic manifestations such as epilepsy, cognitive impairment and autism spectrum disorder. mTOR inhibitors have successfully been used to treat TSC-related manifestations in older children and adults. However, data on their safety and efficacy in infants and young children are scarce. The objective of this study is to assess the utility and safety of mTOR inhibitor treatment in TSC patients under the age of 2 years.

Results

A total of 17 children (median age at study inclusion 2.4 years, range 0–6; 12 males, 5 females) with TSC who received early mTOR inhibitor therapy were studied. mTOR inhibitor treatment was started at a median age of 5 months (range 0–19 months). Reasons for initiation of treatment were cardiac rhabdomyomas (6 cases), subependymal giant cell astrocytomas (SEGA, 5 cases), combination of cardiac rhabdomyomas and SEGA (1 case), refractory epilepsy (4 cases) and disabling congenital focal lymphedema (1 case). In all cases everolimus was used. Everolimus therapy was overall well tolerated. Adverse events were classified according to the Common Terminology Criteria of Adverse Events (CTCAE, Version 5.0). Grade 1–2 adverse events occurred in 12 patients and included mild transient stomatitis (2 cases), worsening of infantile acne (1 case), increases of serum cholesterol and triglycerides (4 cases), changes in serum phosphate levels (2 cases), increase of cholinesterase (2 cases), transient neutropenia (2 cases), transient anemia (1 case), transient lymphopenia (1 case) and recurrent infections (7 cases). No grade 3–4 adverse events were reported. Treatment is currently continued in 13/17 patients. Benefits were reported in 14/17 patients and included decrease of cardiac rhabdomyoma size and improvement of arrhythmia, decrease of SEGA size, reduction of seizure frequency and regression of congenital focal lymphedema. Despite everolimus therapy, two patients treated for intractable epilepsy are still experiencing seizures and another one treated for SEGA showed no volume reduction.

Conclusion

This retrospective multicenter study demonstrates that mTOR inhibitor treatment with everolimus is safe in TSC patients under the age of 2 years and shows beneficial effects on cardiac manifestations, SEGA size and early epilepsy.

The role of mTOR inhibitors in preventing epileptogenesis in patients with TSC: Current evidence and future perspectives

Tuberous sclerosis complex (TSC) is one of the most common genetic causes of epilepsy. Mutations in the TSC1 or TSC2 genes lead to the dysregulation of the mechanistic target of rapamycin (mTOR) pathway. This mTOR pathway hyperactivation is associated with several processes resulting in epileptic conditions. The occurrence of seizures and their treatment outcomes seem to play a crucial role in cognitive and behavioral developments in patients with TSC. Mechanistic target of rapamycin inhibitors have been proven to be effective in epilepsy treatment in individuals with TSC. Specifically, because of their disease-modifying mechanism of action, they have the capability to prevent epileptogenesis in patients with TSC. This article will provide an overview of the current evidence of and delineate future perspectives for mTOR inhibitors and their role in preventing epileptogenesis.

Rapid Regression of Prenatally Identified Intrapericardial Giant Rhabdomyomas with Sirolimus

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Giant cardiac rhabdomyomas were identified on fetal echocardiography.

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The rhabdomyomas were unusually located in the pericardial space.

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Rapid regression and hemodynamic improvement were seen with sirolimus therapy.

Giant left ventricular rhabdomyoma treated successfully with everolimus: case report and review of literature

IntroductionIntracardiac rhabdomyomas can cause severe ventricular dysfunction and outflow tract obstruction.Case reportA term newborn infant with antenatal diagnosis of giant left ventricle rhabdomyoma presented with cardiac failure and duct-dependent systemic circulation after birth. She was treated successfully with everolimus, showing decrease in tumour size and improvement in left ventricular ejection fraction.DiscussionTumour regression rate was 0.32 cm2/day and improved to 0.80 cm2/day with the use of everolimus. Herein we report a newborn with inoperable giant left ventricular cardiac rhabdomyoma and significant regression of the tumour. To our knowledge, this is the largest left ventricular rhabdomyoma reported. A review of the literature was undertaken for comparison.

CONCLUSION

Everolimus has proven to be efficacious in size reduction of cardiac rhabdomyomas in cases when surgical resection is not possible.

Sirolimus in Infants with Multiple Cardiac Rhabdomyomas Associated with Tuberous Sclerosis Complex

INTRODUCTION

Cardiac rhabdomyomas represent a frequent manifestation of tuberous sclerosis. Tumor growth, mainly prenatally, can result in intrauterine fetal or neonatal deaths in almost 10% of patients.

CASE REPORT

We treated 3 consecutive infants aged less than 12 months with sirolimus, an oral mTOR inhibitor. All patients achieved significant reductions in cardiac rhabdomyomas. A complete response was documented in 2 patients, while a partial response with tumor debulking greater than 50% was seen in the other one. The median time to best cardiac response was 1.9 months in all patients, and 3.3 months in those with complete response. The side effects profile was acceptable.

CONCLUSION

Sirolimus may have a significant role in promoting natural regression of cardiac rhabdomyomas. Prospective clinical trials are needed.