GP66 Fatal case of multiple embryonal tumors in a child with beckwith-wiedemann syndrome

Beckwith-Wiedemann syndrome (BWS) is the most common genetic cause of overgrowth in early childhood and also the most common syndrome caused by the loss of imprinting. Depending on the underlying molecular genetics, it can increase the risk of development of embryonal tumours by up to 20%. Children with BWS benefit from radiographic and biochemical screening. In case of early detection of malignancy they are promptly treated with similar or better survival than general population. Multiple concomitant tumours remain rare. We report a case of a 4-year-old boy diagnosed with BWS at birth. This was based on his clinical features and subsequently confirmed genetically as paternal uniparental disomy (11p15.5). His first malignancy was a hepatoblastoma at birth, treated by surgical resection and chemotherapy. Four months later, a suspected left sided nephroblastoma was identified and left sided nephrectomy was performed. Histology revealed nephroblastomosis. 2 years later, a nephroblastoma in the upper pole of right kidney was described. It responded well to chemotherapy and was resected using nephron sparing surgery technique. Three months into adjuvant chemotherapy, another tumor developed in the lower lobe of right kidney. This progressed despite an intensified chemotherapeutic treatment and a nephrectomy was carried out rendering the patient anephric. Radiation to the abdomen with a boost to the site of the right kidney was offered to the boy, while he was on dialysis. Within 2 months of completion of radiation, a new right sided mass was described on follow-up abdominal imaging. At that point all further oncologic treatment was deemed futile and the boy passed away 6 weeks later. A review of our 30 year patient registry revealed 295 patients diagnosed with nephroblastoma between July 1988 and December 2018. There were 7 children with clinically suspected Beckwith-Widemann syndrome, 2 of those confirmed genetically. All but one were successfully treated without relapse, synchronous or metachronous malignancy. Unlike other tumour predisposition syndromes, the increased risk of malignancy in BWS reduces sharply after 8 years of life. Synchronous or metachronous malignancy in this population remain exceedingly rare, making our patient an unfortunate exception. Patients with BWS rendered anephric following bilateral nephroblastoma resection have to remain in complete remission for 2 years post completion of oncological therapy before being considered for a renal transplant. Should they remain without evidence of disease, they are good candidates for kidney transplant, with similar rates of survival and graft rejection to other transplantees.