Occult Nesidioblastosis Detected by 111In-Pentetreotide Single-Photon Emission Computed Tomography

Nesidioblastosis, also known as persistent hyperinsulinemic hypoglycemia, is usually observed in children and infants, although more recently adult-onset nesidioblastosis has also been described. We present a case of nesidioblastosis in a 78-year-old man that was detected by 111In-pentetreotide single photon emission computed tomography (SPECT/CT). The patient was transferred to our hospital's emergency department in a hypoglycemic coma. Dynamic enhanced CT could detect no lesion in the pancreas, but an 111In-pentetreotide SPECT/CT scan performed after a similar episode four weeks later showed increased focal uptake at the head of the pancreas. The results of a selective arterial calcium injection test were negative. After careful consideration and discussion among colleagues, surgical intervention was selected, and a pancreaticoduodenectomy was performed. On histology, there were elevated numbers of Langerhans islets in the pancreatic head, and the islets themselves appeared enlarged. Hypertrophic β-cells comprised the majority, but α-cells, δ-cells and pancreatic polypeptide were also detected in the islets. Based on the histopathological results and repeated hyperinsulinemic hypoglycemic crises, the patient was finally diagnosed with adult-onset nesidioblastosis. He had no hypoglycemic symptoms during outpatient follow-up examination. Since 111In-pentetreotide SPECT/CT may be able to detect nesidioblastosis, clinicians should consider this relatively new-modality examination when encountering such cases.