Warren et al. in Melbourne, Australia, report the fascinating case of a school teacher diagnosed with an insulinoma in 1992, when he was aged 38. Their report has many learning points, including the diagnostic difficulty presented by the condition: due to behavioural change caused by hypoglycaemia, the subject spent some time in an inpatient psychiatry unit before the correct diagnosis was reached.

In the early 1990s, despite repeated imaging, invasive localisation studies and two surgeries, the insulinoma could not be found. In 1993, the medical team commenced treatment with oral diazoxide, with subsequent marked improvement in the patient’s symptom burden (he was able to return to work), and a manageable side effect profile (hirsutism and mild peripheral oedema).

In 2014, the insulinoma was finally localised with ⁶⁸Ga-NOTA-exendin-4 positron emission tomography/computed tomography scanning. However, after advice from the surgical team that definitive treatment would probably require total pancreatectomy, the patient opted to continue with medical treatment alone. Now, in 2020, he continues on diaxozide, and remains very well.

The authors comment that this provides a useful reflection on how investigation of insulinoma (especially the available imaging modalities) has changed in the past 30 years. To their knowledge, the use of diaxozide for a period as long as 27 years has not been reported previously. For those people with an insulinoma in whom surgery may not be possible, or may be declined, this case may well be of value to their medical team.

Read the full article in Endocrinology, Diabetes & Metabolism Case Reports doi:10.1530/EDM-20-0132