Endocrine Abstracts

Tumour induced hypoglycaemia is a rare disorder occurring in cancer patients caused by variety of tumours including islet and non-islet tumours. Non-islet cell tumour induced hypoglycaemia (NICTH) is rare paraneoplastic disorders normally associated with pleural solitary fibrous tumour but can also rarely occur in extra thoracic site.

We describe an 86-year-old man not known to have diabetes mellitus who presented with 3-month history of early morning headache and dizziness relieved by consuming large amount of fizzy sweet drink. On examination, he was noted to have large palpable mass on the left upper quadrant. Initial inpatient investigations during symptoms showed plasma glucose of 2.4 mmol/l, insulin <1.0 pmol/l (17.8–173), C peptide 81 pmol/l (298–2350), 3-hydroxybutyrate <0.1 mmol/l, free fatty acid 0.3 mmol/l, negative serum sulphonyurea screen, and normal short Synacthen test. CT scan of the abdomen revealed huge solitary 22×19×16 cm well defined, rounded solid heterogeneous retroperitoneal mass with internal ill-defined areas of necrosis. There was no evidence of metastasis on further full body scan. Further work up showed raised IGF2 94.5 nmol/l, IGF1 7.1 nmol/l, and raised IGF2:IGF1 ratio 13.3 (normal ratio <10). Subsequent biopsy of the retroperitoneal mass demonstrated spindled shape cells showing mild to moderate nuclear atypia appearance consistent with malignant solitary fibrous tumour. Investigations were consistent with diagnosis of NICTH secondary to extra thoracic solitary fibrous tumour. He was managed conservatively with oral dexamethasone 1.5 mg o.d. which resolves the recurrent hypoglycaemic episodes. Surgical resection was not pursued, as he was deemed not fit for surgery.

In summary, we have described a rare phenomenon of Doege–Potter syndrome, a paraneoplastic phenomenon of hypoglycaemia associated with rare extra thoracic solitary fibrous tumour. It is important to investigate the aetiology thoroughly as management can be tailored individually for each patient.