Beckwith-Wiedemann syndrome (BWS) is a congenital tumor-predisposition syndrome of which around 70% develops because of the methylation defects in the imprinted genes at chromosome 11p15.5. KCNQ1OT1 hypomethylation is the most common underlying genetic aberration in sporadic the BWS, accounting for 50% of the sporadic cases but confers the least tumor risk. We present a 5 month-old girl who presented with an excessive weight gain, cushingoid face, arrested growth in height and head circumference since 2 months of age. She was born following an in vitro fertilization (IVF) pregnancy to non-consanguineous parents with negative familial history for malignancies. She had signs of Cushing syndrome, nevus flammeus between eyebrows, microcephaly, a palpable mass on upper right abdomen and Tanner stage 2 pubarche at physical examination. Her biochemical, imaging and immunohistochemical established the diagnosis of adrenocortical carcinoma as a cause of Cushing syndrome. There was no adrenal cortex cytomegaly at histopathological evaluation. Methylation analysis of the imprinted domains at chromosome 11p15.5 revealed hypomethylation at KvDMR(KCNQ1OT1gene). Except for a nevus flammeusand adrenocortical carcinoma, she had no features of the BWS. Growth rate of height and head circumference has turned to normal after tumor resection. This case establishes that KCNQ1OT1hypomethylation should not only be considered in cases with a clear BWS phenotype but in all pediatric cases of apparently sporadic adrenocortical carcinoma.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology