Introduction: Pituitary adenomas account for 10% of intracranial tumours and are almost always benign. In some individuals, who may have a pre-existing adenoma, the pituitary gland undergoes remarkable hyperplasia especially during pregnancy, due to increase in oestrogen levels leading to increase in the tumour volume causing mass effects. This case report reviews a pregnancy with incidental finding of pituitary macro adenoma causing visual field defect, its management and further follow up.
Case Presentation: We present a 32 years old pregnant female of 37 weeks gestational age (G1, P0) presenting to the emergency department with 1 week history of sudden deterioration in visual acuity. Visual field examination revealed a supero-temporal defect in the right and left eyes. MRI showed a pituitary macro adenoma measuring 16 + 12 + 15 mm, extending to suprasellar region causing upward displacement and compression of optic chiasma. Blood tests including pituitary profile were within normal reference range except mildly raised prolactin. She underwent elective lower caesarean section under hydrocortisone cover in view of her visual field defect. Following the delivery, her visual acuity improved significantly. A follow up MRI pituitary with contrast done 2 months later showed a reduction in the size of adenoma measuring about 9 mm. Patient was started on cabergoline and has been advised to use contraceptives and to seek help before planning for next pregnancy.
Discussion: Managing macro adenoma during pregnancy is challenging. Symptomatic macro adenoma should be an indication for caesarean section. In our case, the tumour was diagnosed after conception. Hence for the future pregnancies, an MRI should be done before conception to document tumour size with a monthly follow up and visual field examination at every trimester. Patients must be informed about the relatively higher risk of tumour enlargement and the importance of treatment before conception. Patients with large macro adenomas and those with suprasellar extension are strongly discouraged from conceiving until definitive therapy is undertaken. Surgery is an option in cases with no tumour reduction with medical treatment, or in those who developed tumour growth in a previous pregnancy. What can be more challenging in planning for the future pregnancies is that surgery of the gland can lead to infertility whilst future pregnancy may again cause macro adenoma which may even lead to blindness as pituitary once enlarged, never shrinks back to its normal size.