Spontaneous regression of a large rhabdomyoma of the interventricular septum

Clinical, cellular, and molecular characterisation of cardiac rhabdomyoma in tuberous sclerosis

BACKGROUND

Rhabdomyoma is the most common cardiac tumour in children. It is usually associated with tuberous sclerosis complex caused by mutations in TSC-1 or TSC-2 genes. This tumour typically regresses by unknown mechanisms; however, it may cause inflow or outflow obstruction that necessitates urgent surgery. Here we investigate the clinical features and the genetic analysis of patients with tuberous sclerosis complex presenting with large rhabdomyoma tumours. We also investigate the potential role of autophagy and apoptosis in the pathogenesis of this tumour.

METHODS

All the patients with cardiac rhabdomyoma referred to Aswan Heart Centre from 2010 to 2018 were included in this study. Sanger sequencing was performed for coding exons and the flanking intronic regions of TSC1 and TSC2 genes. Histopathological evaluation, immunohistochemistry, and western blotting were performed with P62, LC3b, caspase3, and caspase7, to evaluate autophagic and apoptotic signaling.

RESULTS

Five patients were included and had the clinical features of tuberous sclerosis complex. Three patients, who were having obstructive tumours, were found to have pathogenic mutations in TSC-2. The expression of two autophagic markers, P62 and LC3b, and two apoptotic markers, caspase3 and caspase7, were increased in the tumour cells compared to normal surrounding myocardial tissue.

CONCLUSION

All the patients with rhabdomyoma were diagnosed to have tuberous sclerosis complex. The patients who had pathogenic mutations in the TSC-2 gene had a severe disease form necessitating urgent intervention. We also demonstrate the potential role of autophagy and apoptosis as a possible mechanism for tumourigenesis and regression. Future studies will help in designing personalised treatment for cardiac rhabdomyoma.

Spontaneous Regression of a Mandibular Plasmacytoma in a Juvenile Dog: A Case Report

A 4 mo old female Finnish lapphund presented for further investigation of a swelling of the right rostral mandible. A computed tomography scan showed the swelling to be an expansile and osteolytic mandibular lesion. Histopathology revealed a poorly differentiated, moderately well-demarcated, unencapsulated, highly infiltrative round cell neoplasm, and immunohistochemistry was supportive of a plasmacytoma. Performance of a rostral partial mandibulectomy was initially discussed with the owners, but the lesion improved spontaneously both clinically and on repeated computed tomography scanning before surgery could be performed. It subsequently almost completely resolved 6 mo after diagnosis. Hypotheses for spontaneous regression of the lesion are discussed and the human literature is briefly reviewed.

Autopsy case of right ventricular rhabdomyoma in tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is a genetic multisystem disorder characterized by widespread hamartomas in several organs, including the brain, heart, skin, eyes, kidney, lung, and liver. Rhabdomyoma is the most common cardiac tumor diagnosed in fetuses, neonates and infants, and is closely linked to TSC. Here we describe an autopsy case of right ventricular rhabdomyoma in TSC. The deceased was a 3-month-old male infant, and TSC with a cardiac tumor had been diagnosed before his death. Since the cardiac tumor had not been physically blocking the blood flow, he had not undergone surgical intervention. At autopsy, the patient's height was 62 cm and his body weight was 6 kg. The heart weighed 37.3 g and the right ventricle was filled with the tumor. The tumor measured 2.1 cm × 1.6 cm, being a fusion of multiple tumors with several attachment sites to the myocardium. Histologically, the tumor was diagnosed as a rhabdomyoma, and was positive for mammalian target of rapamycin (mTOR). The brain weighed 795.0 g, without hydrocephalus. The cut surface of the brain revealed multiple cortical tubers and subependymal nodules. Through screening for the TSC1 (hamartin) and TSC2 (tuberin) genes, a nonsense mutation, c.1108C>T:p.Gln370^∗, was detected in the TSC2 gene. Immediate cause of death was determined to be ventricular obstruction by a cardiac rhabdomyoma with insidious growth. This case highlights the need for forensic pathologists to perform a complete autopsy to determine the cause of sudden death with cardiac tumor, including genetic examination.

Heart Tumors in 33 Fetuses - Review of Twenty-Two Years of the Single-Centre Experience

INTRODUCTION: Cardiac tumors (CT) have been diagnosed since the eighties of the last century. The three most commonly diagnosed types of CT are rhabdomyomas, teratomas and fibromas. Severe fetal disturbances, such as arrythmias, fetal hydrops, ventricular obstructions, may be associated with the heart tumor.

AIM OF THE STUDY: To present the key role of the echocardiographic examination in the perinatal care and to present some demographic changes in this population of the youngest patients.

MATERIAL AND METHODS: From the Filemaker database of the Department for Diagnosis and Prevention of Congenital Malformations, Polish Mother’s Memorial Hospital & Medical University of Lodz, all cases with prenatal diagnoses of cardiac tumor in singleton pregnancy were compiled over a 22-year period (1993–2015). 33 cases of heart tumors in fetuses had 72 fetal echo examinations. The average number of cases per year was 1,5 (range 1 – 5). The retrospective analysis of the material was performed using the Statistica package. The analysis included the assessment of the cardiovascular condition defined by Cardiovascular Profile Score, location and number of tumors; age, past obstetric history, place of residence of the mother, type of delivery and neonatal follow-up.

RESULTS: The number of fetuses with cardiac tumor cases did not increase during this period. The maternal age was 28,1 years (± 5,2 years) and was decreasing over time. The primigravidae constituted 60% of examined population. The history of past miscarriages was observed in 26% of women. The majority of tumors were detected and diagnosed in the third trimester – at mean 29,6 hbd, but the diagnosis was made earlier in the past decades (regression analysis, p=0,042). The average duration of pregnancy was 36,6 hbd (range: 27-42 hbd). There was no statistical difference between decades in term on pregnancy duration.

The cardiac tumors were more frequent in the female fetuses (71,4% to 28,6%; X2 test; p=0,006). The proportions between the groups of single and multiple tumors changed in last five years – currently the multiple tumors are more frequent (87,5%). The mortality in the group of single tumors was twice as high as in the group of multiple tumors. The percentage of cesarean sections between 1993 and 2005 was 67% and between 2006 and 2015 was 75% (p=0,63). The mortality of neonates with cardiac tumors declined over the period taken into account.

CONCLUSIONS: The perinatal care of the fetuses with cardiac tumors improved over last 20 years. The characteristics of analyzed population had shown that fetal CTs affected healthy, young mothers, more often primigravidae, more often female fetuses. The prevalence of CTs did not increase over time. The gestational age at the time of the diagnosis decreased, thus the period of fetal echo monitoring increased. However, the rate of cesarean sections also increased, which requires further studies and explanations.