Giant Prolactinoma with intracerebral involvement presenting as seizures.

Vakil Z, Johnston C.


We report an interesting case of a 30 year old male who was referred to the endocrine firm after an MRI brain carried out by the neurologist for presumed partial seizures with headache revealed a large sellar and suprasellar mass extending into the inferomedial aspect of the left frontal lobe. There was extension into the cavernous sinus but surprisingly no encroachment onto the optic chiasm and indeed his visual fields were normal.

Biochemical testing revealed a prolactin level of 98,692. There was suppression of testosterone down to 4. Growth hormone was not measured. Inspite of the extensive nature of the tumour, the rest of his pituitary profile was suprisingly intact with a 9:00 am cortisol of 608 and normal thyroid function.

He was treated medically with a rapidly escalating dose of cabergoline. He was started on 500µg for the first week and then 500 µg twice weekly for the second week, going  on to 1 mg twice weekly and finally 2 mg twice weekly. He responded extremely well to medical treatment and did not require any anti-epileptic medications. His prolactin went down to 1400 over a period of 3 months and a repeat MRI showed substantial reduction in the size of the tumour.

Unique features of this case include the extremely high prolactin levels seen (close to 100,000), intracerebral invasion of the tumour without any local compression on the optic chiasm and the unusual presentation of seizures and blackouts necessitating referral to a neurologist initially.