Endocrine Abstracts

A 44-year old man, previously well, presented with acute confusion and having collapsed at home. His capillary blood glucose was 2.2mmol/L and he was resuscitated with an intravenous dextrose infusion. His collapse had resulted in a fracture to his right neck of femur.

Given the possibility of a pathological fracture he had a bone scan, which revealed widespread bony metastasis. In search for the primary source, an abdominal computerised tomography (CT) scan revealed a lobulated calcified retroperitoneal mass arising from the medial aspect of the left kidney with para-aortic lymphadenopathy. A tentative diagnosis of metastatic renal cell carcinoma was made.

Investigations of his hypoglycaemia revealed inappropriately high IGF-II levels with low IGF-I and high IGF-II/IGF-I ratio consistent with non-islet tumour hypoglycaemia. An ultrasound-guided biopsy was performed and based on immunohistochemistry studies and electron microscopy findings; a diagnosis of a malignant renal neuroendocrine tumour (NET) was reached. Chromogranin A and B levels were elevated. Fasting gut hormones, pituitary hormones, 24-hour urinary catecholamines and 5-Hydroxy Indole Acetic Acid were unremarkable.

Following a multidisciplinary meeting, palliative radiotherapy was given for the bony metastasis and adequate analgesia was maintained. For the hypoglycaemic episodes he required continuous 10% dextrose infusions, high dose prednisolone; however, partial improvement of his hypoglycaemic episodes was only noted with the introduction of subcutaneous octreotide. Growth hormone treatment was considered, but his health deteriorated rapidly, and he died four months after his first presentation. Post mortem examination confirmed a renal neuroendocrine tumour with widespread dissemination.

This is the first case of a renal neuroendocrine tumour, leading to non islet cell tumour hypoglycaemia through overproduction of IGF-II, and the case serves to highlights the complexities encountered in the diagnosis and management of neuroendocrine tumour.