Endocrine Abstracts

A 45-year-old lady presented with a 12-month history of blurred vision. Visual assessment revealed a bitemporal hemianopia and CT scan demonstrated a large pituitary tumour with lateral and suprasellar extension. A GTT showed her growth hormone was raised basally at 7.5 milliunits per litre and incompletely suppressed to 5.7 milliunits per litre confirming acromegaly. Transsphenoidal hypophysectomy was performed. Histology confirmed a somatoptroph adenoma. Post operatively she had anterior hormone deficiency. She underwent external pituitary irradiation. Initially there was a good response; visual acuity and fields of vision became normal. There was shrinkage of the tumour on CT scan and a fall in GH levels, IGF1 levels remained elevated. (30-60 nanomols per litre,NR 3-30)

She remained well for 8 years, when she re-presented with blurring of vision. She was shown to have a decreased visual acuity (N8 bilaterally) and a recurrence of her bitemporal hemianopia. MRI demonstrated a large pituitary adenoma, eroding the pituitary fossa, extending laterally and superiorly. Due to the regrowth of the tumour and because of promising results in the UK in shrinkage of growth hormone secreting tumours after octreotide as a primary medical therapy, a short trial of a somatostatin analogue (sandostatin 100micrograms, three times daily) was commenced. Her visual acuity and perimetry returned to normal within three days and she was commenced on sandostatin LAR 20 milligrams every 28 days. Further MRI imaging after 1 week showed shrinkage of the tumour by a few millimetres only and a further scan 5 months later failed to show any improvement in tumour size but the patient remains well with normal vision and is reluctant to consider further surgery.

Sandostatin analogues have been shown to be effective as a primary therapy in acromegaly without visual impairment. In this case there has been a restoration of vision but the long-term outlook remains guarded without significant tumour shrinkage.