Extreme pituitary hyperplasia of normal pregnancy presenting as a macroprolactinoma
Shamasunder Acharya1, Sam Philip1, Peter Danielian2, Shona Olson1, John Bevan1 & Prakash Abraham1
Case report: A 33-year-old pregnant Nigerian woman presented at 37 wks gestation with a 2-week history of frequent headaches and visual disturbance. She had persistent galactorrhoea following previous pregnancy in 1998, which settled after a short course of bromocriptine. On examination, she had classical bitemporal hemianopia. Her prolactin was raised at 19,220 mU/L (higher than expected in a normal pregnancy), random cortisol 553 nmol/L and thyroid function tests satisfactory. Macroprolactinoma was suspected and an urgent MRI scan showed a 1.5×2.4×1.8 cm pituitary macroadenoma with optic chiasm compression. In view of the visual disturbance, labour was induced with a successful outcome. Her headache and visual disturbance resolved promptly following delivery and visual fields were completely normal. She underwent a combined metoclopramide and short Synacthen test at 6 weeks and was commenced on cabergoline (0.5 mg, twice a week) pending the result. However, she had normal prolactin and cortisol dynamic responses (basal prolactin 4400 mU/L raising to 38,700 at 30 min; cortisol 256 nmol/L raising to 733 nmol/L at 30 min). A follow-up MRI showed a normal pituitary gland (maximum height 9 mm) and previous macroadenoma had completely disappeared. Cabergoline was discontinued after 8 weeks therapy (only 8 mg total). Her latest prolactin (6 months postnatal) is 570 mU/L she is well and considering a further pregnancy.
Discussion: Previous imaging studies have shown approximate doubling of pituitary volume in normal pregnancy. Normal metoclopramide responses and rapid resolution of pituitary mass on postnatal MRI in this case, strongly suggests the possibility of extreme pituitary hyperplasia of normal pregnancy. Published case-reports are very rare and clinicians should be aware of this condition so that inappropriate therapy may be avoided.
Published case-reports are very rare and clinicians should be aware of this condition so that inappropriate therapy may be avoided.