Successful Management of an Infant with Congenital Focal Hyperinsulinism with No Apparent Lesion During Surgery

C ongenital hyperinsulinism (CHI) is a heterogeneous disease caused by defects in regulating insulin secretion.It can potentially lead to permanent neurological damage, prompt diagnosis and appropriate management are important. [1,2]ere are three histological forms of CHI; focal form (F-CHI), diffuse form (D-CHI), and atypical.These are clinically indistinguishable but differ at least partially in the type of genetic defect. [3]F-CHI is caused by a heterozygous ABCC8 or KCNJ11 gene mutation inherited paternally along with somatic loss of the 11p15 region of the maternal chromosome and encompasses 30-40% of cases with CHI. [4]ngenital hyperinsulinism (HI) is the leading cause of persistent hypoglycemia in infants and children.Focal pancreatic lesions account for 30-40% of cases with congenital HI.With early diagnosis, these patients can be treated by resection of the lesion, making long-term medical care unnecessary.In this case, a 5-day-old newborn boy presented with convulsion due to severe and persistent hypoglycemia at his hospitalization in neonatal intensive care unit.Laboratory studies revealed very low levels of ketone bodies with inappropriately normal insulin levels during hypoglycemia.The patient was unresponsive to diazoxide treatment.The molecular genetic analysis revealed a heterozygous pathogenic variant in the ABCC8 gene.18F-DOPA-PET/CT scan showed increased uptake of 18F-DOPA consistent with focal lesion at the tail of the pancreas.A focal pancreatectomy operation was performed when he was three months old.Histopathological evaluation confirmed focal endocrine cell hyperplasia.Hypoglycemia did not recur after the operation.CHI patients with ABCC8 / KCNJ11 mutation are not easy to manage with pharmacotheraphy.In the case of an identifiable focal lesion associated with CHI, surgery is the most preferred option.In focal CHI, as in our case, the lesion may not be visually evident and requires a surgeon experienced in CHI.