Insulinomas are often difficult to localize. We present a 47-year-old woman who had recurrent neuroglycopenic symptoms and positive Whipple triad for 28 months. The 14 hours of fasting test confirmed the diagnosis of endogenous hyperinsulinemic hypoglycemia which is highly suspicious for the presence of an insulinoma. Previously performed MRI, endoscopic ultrasound, 111In-pentetreotide SPECT/CT, and 68Ga-DOTA-exendin-4 PET/CT did not show any evidence of an insulinoma. Subsequently, 68Ga-DOTA-exendin-4 PET/CT was repeated with the previous infusion of a colloidal volume replacement fluid (Gelofusine), known to reduce 68Ga-DOTA-exendin-4 accumulation in the kidneys. Consequently, the insulinoma was unmasked from the left kidney, allowing curative surgery.
From the *Clinic of Radiology and Nuclear Medicine, and
†Division of Endocrinology, Diabetology and Metabolism, University Hospital Basel, Basel, Baselland, Switzerland.
Received for publication August 21, 2018; revision accepted January 23, 2019.
Conflicts of interest and sources of funding: Swiss National Science Foundation grant number 320030-152938 and Desirée & Niels Yde's Foundation grant number 389-12. None declared to all authors.
Correspondence to: Kwadwo Antwi, MD, Universitatsspital Basel, Basel, Baselland, Switzerland. E-mail: Kwadwo.firstname.lastname@example.org.