An interesting case of intrasellar cavernous carotid aneurysm mimicking pituitary adenoma
Cynthia Mohandas & Ian Scobie
A 34-year-old lady presented with irregular periods but no galactorrhoea. A prolactin level was 1326 mU/l.Clinical examination-Normal. BMI 26 and visual fields were full to confrontation. MRI scan of pituitary was reported as large pituitary macroadenoma measuring 11× 11× 12 mm denting the optic chiasm. Results of other endocrine tests were as follows; cortisol 265 nmol/l, TSH 0.32 mU/l, FT4 8.5 pmol/l, FSH 4 U/l, LH 1.6 U/l, oestradiol 104 pmol/l, GH 8.4 mU/l, IGF1 125 nmol/l.
Although it was very suspicious of a non- functioning pituitary macro adenoma, a decision to treat her with Cabergoline 500 mcg once weekly was commenced due to high levels of prolactin. Interestingly there was prompt reduction in her prolactin levels to 21 mU/l after 6 months. Her thyroid function tests normalised and her menstrual cycles that was always six-weeks length reduced to a regular 28-days cycle. However she still had persistent headaches, so her MRI scan was repeated and she was referred to a combined pituitary clinic. A pituitary radiologist now described it as an 11 mm lesion with intermediate T1 waited signal. So CT angiogram was performed the same afternoon. This showed a 9 mm right-sided intrasellar cavernous carotid aneurysm.
The case was then referred to joint neurovascular clinic. The risk of rupture was relatively low, so the opinion was that; the risk of interference at this stage was greater than the risk of pursuing a conservative line. From endocrine prospective she remains on Cabergoline 250 mcg once weekly which maintains normal pituitary function.
Conclusion: This is a really fascinating case and is intriguing. Although we did not make a correct diagnosis initially, the combined pituitary clinic was reassured they did not intervene at that point which could have let to permanent stroke and death. This patient still remains stable in her recent clinic visit.