Endocrine Abstracts

Erratic release of insulin accounts from periodic nature of the symptoms in insulinoma. Islet-amyloid polypeptide has been demonstrated in human insulin producing tumours- insulinoma. Presence of amyloid tissue has been demonstrated in pancreatic islets in patients with diabetes mellitus. Impaired islet function is a feature of diabetes mellitus. Hyperglycaemia, as in diabetes, enhances amylin secretion. Presence of insulinoma has been documented in past but insulionoma presenting at the same time, as diabetes mellitus is not described before. Similarly, amelioration of diabetes in a patient with insulinoma is rarely described.

We report a case in which insulinoma surgery led to complete reversal of diabetes mellitus.

A 77-year-old previously healthy woman presented with generalised tiredness and feeling generally unwell. Periodic episodes of confusion were also described. Oral glucose tolerance test (OGTT) confirmed diabetes mellitus with fasting glucose as 7.2 and 2 hours 16.2 mmol/l. She was appropriately counselled. She continued to have episodic confusion and was admitted for 24 hour fast to detect hypoglycaemia. Her blood glucose dropeed to 1.9 mmol per litre and simultaneous C peptide levels were 1788 pmol per litre with proinsulin levels raised to 104 pmol per litre. No other pancreatic peptide was detected.

Abdominal imaging (USG and CT scan Abdomen) showed a pancreatic nodule, at the junction of head and neck of pancreas, which was surgically removed. Biopsy showed presence of amyloid tissue in islet cells. She remained well and subsequent OGTT was normal and her confusion episodes disappeared.

Complete reversal of diabetes following insulinoma surgery has not been described in the past.