Surgical management and long-term outcome in giant skull base prolactinomas

Introduction: Giant Prolactinomas are a rare category of skull base tumors. We report the first series of long-term follow-up and outcome of Giant Prolactinomas. Methods: Retrospective chart and clinical review of over 2,000 cases of pituitary tumors presenting to our institution, out of which 10 prolactinomas met the criteria for inclusion in our study (prolactin level greater than 500, radiologie diameter greater than 4 cm, and clinical signs of hyperprolactinemia). Patients were followed for a minimum of 10 years after initial treatment. Results: Over 90% of our series were cured by medical treatment with bromocriptine alone. Tumor volume was decreased by 60%, at a faster rate and in greater quantity when treated with bromocriptine. Conclusions: In Giant Prolactinomas, prolactin level does not correlate with size. Our main indication for early surgery is intra-tumoral hematoma. Indications for late surgery are: CSF leak, medical failure/resistance or an increasing prolactin level despite medical therapy. Measuring prolactin levels in suspicious sellar/suprasellar lesions may be diagnostic and prevent unnecessary surgery. Giant Prolactinomas may be a separate category of prolactin-secreting skull base tumors altogether that arise from cells that may become invasive.