Lasting F-DOPA PET Uptake after Clinical Remission of the Focal Form of Congenital Hyperinsulinism

Background: Positron emission tomography (PET) using 18F-DOPA is a useful tool for detecting the focal forms of congenital hyperinsulinism. 18F-DOPA is taken up by aromatic L-amino acid decarboxylase in pancreatic β-cells. However, the role of this enzyme in insulin secretion is unknown. Subjects and Methods: A Japanese boy who presented with symptomatic hyperinsulinemic hypoglycemia at the age of 2 days and spontaneous resolution at 1 year and 10 months was subjected to mutational analysis and repeated 18F-DOPA PET scans. Results: Mutational analysis revealed a paternally inherited monoallelic mutation, c.4186G>T (p.D1396Y), in the ABCC8 gene, and an 18F-DOPA PET scan revealed focal uptake in the body of the pancreas. The patient was successfully treated with frequent feeding. A follow-up PET scan revealed virtually identical uptake to that observed previously. However, in the arterial stimulation-venous sampling procedure, no significant insulin release was observed. He was placed on a normal diet, and no hypoglycemia recurrence was observed. Conclusion: This case demonstrates two important findings. Firstly, the uptake of 18F-DOPA does not correlate with the insulin-secreting capacity of the lesion. Secondly, clinical remission could be a functional process not necessarily accompanied by the apoptotic death of abnormal β-cells. Copyright © 2011 S. Karger AG, Basel [PUBLICATION ABSTRACT]