SUN-274 Unusual Case of Beckwith Weidemann Syndrome with Spontaneous Resolution of a Hepatic Mass

Abstract

Background: Beckwith-Wiedemann Syndrome (BWS) is an overgrowth syndrome with risk for embryonal tumors (8-10%) like Wilms tumor, hepatoblastoma, adrenal carcinoma and neuroblastoma. Benign tumors like hemangiomas (HM) and hamartomas have rarely been reported. Over expression of paternal growth promoters and decreased expression of maternal growth suppressors are thought to cause these tumors. The highest tumor risk (28%) is in patients with hypermethylation of imprinting center-1 (IC1) which is normally methylated on the paternal allele and unmethylated on the maternal allele, intermediate risk (16%) with paternal uniparental disomy (pUPD) and low risk (2.6%) with imprinting center-2 (IC2) defect which is normally methylated on the maternal allele and unmethylated on the paternal allele. Tumor surveillance with serial serum AFP levels and abdominal US are done from birth to 8 years of age to identify tumors at an early stage. Case: A 46 XX, full term LGA baby with macroglossia, ear lobe creases and an umbilical cord cyst was diagnosed with BWS. Chromosome 11p15 showed hypermethylation of IC1 (H19) and hypomethylation of IC2 (LIT1) confirming BWS due to pUPD. Initial serum alpha fetoprotein (AFP) was 36,790 ng/ml (1212-49039ng/ml) on day of life (DOL) 7, which rapidly increased to 119,797 ng/ml (704-29027ng/ml) on DOL19. The clinical and molecular diagnosis (pUPD) of BWS with highly elevated AFP raised concern for an underlying tumor. Abdominal ultrasound (US) and MRI on DOL 20 showed no mass. Serial AFP levels showed a dramatic decline over the next 3 mo (91681 ng/ml at 1 mo, 24092 ng/ml at 2 mo, 1207 ng/ml at 3 mo) however abdominal US at 3 mo of age showed a hypoechoic mass (0.7x0.5x0.6cm) in the right lobe of the liver. A repeat US at 3.5 mo showed an increase in the size of the mass (1.8x0.8x1.4cm) despite down-trending serum AFP (785 ng/ml). The mass was well circumscribed, heterogenous with calcifications and peripheral flow on US; MRI showed prompt progressive enhancement beginning peripherally and filling in centrally, both suggesting a vascular lesion like a HM. Vigilant follow up with US and serum AFP was continued given the high risk of tumors. Serial US showed a decrease in size of the hepatic mass starting at 4 mo of age (1.1 x 0.6 x 1.1 cm); to 0.8x0.4x0.7cm at 6 mo and complete resolution at 9 mo of age; confirming an involuting HM. The most recent US at 28 mo showed no hepatic mass in conjunction with undetectable serum AFP. Conclusion: This is an unusual case of an isolated hepatic HM in association with BWS, that spontaneously resolved. HM should be considered in the differential of hepatic mass especially with discordant AFP levels. However, given the high risk of tumors conferred by the molecular genetics, continued vigilance is still warranted to identify any new tumor at the earliest.