Treatment of extensively invasive (giant) prolactinomas with bromocriptine.

We report four cases of extensively invasive giant prolactinomas. No tumour was suitable for total or near total resection because of invasion into surrounding bone. All had undergone radiotherapy prior to dopamine agonist therapy. Prolactin levels were between 103,000 mlU/L and 1,700,000 mlU/L at presentation, but all tumours responded to bromocriptine therapy and prolactin levels fell into the normal range in three patients within two to 24 months. The fourth patient's level fell to just above the reference range (700 mlU/L) within 36 months. None of the patients has died of their pituitary tumour or related complications to date. Giant prolactinomas appear to be exquisitely sensitive to treatment with bromocriptine. The role of radiotherapy is unclear, but it might contribute to long term control. Surgery should be limited to control of local complications.