Endocrine Abstracts

The efficacy of dopamine agonist therapy for complex solid and cystic macroprolactinoma is a subject of controversy among endocrinologists. Many believe that such therapy may not result in a clinically significant shrinkage of any cystic component of a macroprolactinomas.

We present a case of cystic macroprolactinoma which responded damatically to dopaminergic therapy with recovery of pituitary function.

A 22 years old male, presented at 14 years of age presented to the paediatric endocrine unit with loss of vision to the left eye. MRI pituitary showed pituitary cystic macroadenoma with suprasellar extension and optic chiasm compromise and visual field testing showed left sided hemianopia. His anterior pituitary hrome profile was as follow: prolactin 18 000 mu/l, random cortisol <20 nmol/l, LH 1.4 IU/l, FSH 3.2 IU/l, TSH 1.51, TT4 31 nmol/l (60–140), Glucagon stimulation test revealed growth hormone defienciey and poor cortisol reserve. He was commenced on thyroxine, hydrocortisone and. He showed remarkable response to bromcriptine, his visual acuity and fields of vision returned to normal. Repeated MRI scan showed reduction in the size of the cystic adenoma with no optic chiasm compromise. Subsequently he was switched to cabergoline twice weekly and his prolactin level fell to normal level 237 mu/l. two years later his pituitary function recovered with peak cortisol 537 nmol/l and peak GH 12.6 mu/l following Insulin tolerance test. However, he remained to require thyroxine replacement only. Subsequent MRI scans of his pituitary revealed no significant tumour residuum and no evidence of pituitary cyst.

Our patient illustrates that dopamine agonist therapy can result in a remarkable shrinkage of macroprlactinoma even in the presence of a cystic component. We suggest that such patients should be given a trial of dopamine agonist therapy as a first line treatment option.