Images from 18F-DOPA Scan in Congenital Hyperinsulinism: Not Always a Clue for Diagnosis

Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycaemia in childhood (Horm Res 70:65-72, 2008; J Clin Endocr Metab 93:869-875, 2008). 18-Fluoro-L-dihydroxy-phenylalanine (18F-DOPA) positron emission tomography (PET) can detect areas of increased activity in the pancreas and may differentiate focal from diffuse CHI (J Clin Endocr Metab 93:869-875, 2008; Radiology 253:216-222, 2009). We here report the case of a girl who complained of recurrent episodes of severe hypoglycaemia despite previous partial pancreatectomy. To evaluate the need for additional surgical intervention, we performed 18F-DOPA PET/computed tomography (CT), which showed a focal lesion corresponding to the anatomical region of the pancreatic tail. On the other hand, abdominal magnetic resonance imaging (MRI) clearly demonstrated that the 18F-DOPA uptake was in a loop of bowel occupying the previous surgical bed. Our case highlights that bowel uptake can be a possible pitfall in the interpretation of 18F-DOPA PET/CT in children affected by CHI, suggesting that when 18F-DOPA PET/CT results do not fit the clinical picture, magnetic resonance imaging (MRI) may allow a more accurate correlation of the radiotracer activity with the underlying anatomical or pathological structure.