Recurrent insulinoma in a 10-year-old boy with Down’s syndrome

Abstract

An insulinoma is a rare tumour with an incidence of four cases per million per year in adults. The incidence in children is not established. There is limited literature available in children with insulinoma, and only one case is reported in association with Down’s syndrome in adults. Insulinoma diagnosis is frequently missed in adults as well as in children. The Whipple triad is the most striking feature although it has limited application in young children. Hypoglycaemia with elevated insulin, C-peptide and absent ketones is highly suggestive of hyperinsulinism. We present a case of 10-year-old boy with Down’s syndrome with recurrent insulinoma. He was initially misdiagnosed as having an adrenal insufficiency and developed cushingoid features and obesity secondary to hydrocortisone treatment and excessive sugar intake. The tumour was successfully localised in the head of the pancreas with an MRI and octreotide scan on first presentation. Medical treatment with diazoxide and octreotide could not achieve normal blood glucose levels. The insulinoma was laparoscopically enucleated and pathological examination confirmed a neuroendocrine tumour. Subsequently, he had complete resolution of symptoms. He had a recurrence after 2 years with frequent episodes of hypoglycaemia. The biochemical workup was suggestive of hyperinsulinism. MRI and PET scan confirmed the recurrence at the same site (head of the pancreas). He had an open laparotomy for insulinoma resection. The pathology was consistent with benign insulinoma, and subsequently, he had complete resolution of symptoms.