Giant prolactinomas: clinical management and long-term follow up
Kalmon Post2002, Journal of Neurosurgery
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Abstract
HE outcome and treatment of prolactinomas have improved dramatically within the past three decades. Transsphenoidal microsurgical resection allows a precise adenomectomy with preservation of normal pituitary function and low complication rates. Although it was initially popular as the treatment of choice in prolactinoma therapy, transsphenoidal adenomectomy had recurrence rates of hyperprolactinemia ranging from 26 to 50% in large surgical series. Although more recent reports with rigorous long-term follow-up review contained reduced postoperative recurrence rates (12-15%), 14,32,49 dopamine agonist drugs are now the treatment of choice for most patients with hyperprolactinemia. Administration of bromocriptine, a semisynthetic ergot alkaloid and long-acting dopamine agonist, results in normalization of prolactin levels in more than 80% of patients with controlled prolactinoma growth. Bromocriptine inhibits secretion and synthesis of prolactin and proliferation of lactotroph cells within the anterior pituitary. Although prolactinoma cells usually remain sensitive to bromocriptine, the drug does not cure these adenomas; discontinu-ation of therapy often results in recurrent hyperprolactinemia. Although prolactinomas are the most common secretory pituitary tumor, giant pituitary adenomas are a rare subcategory of pituitary lesions. Overall, population of giant pituitary adenomas raise distinct and complex management issues because of frequent involvement of the CS and other parasellar and basal forebrain structures. Giant pituitary adenomas with evidence of invasion on neuroimaging have a variable clinical course. On one end of the spectrum, there have been reports of adenomas infiltrating the CS, and on the other, adenomas with a stable course and no growth for years have been observed. The growth rate and growth potential of these tumors has not yet been elucidated. Originally described as having large suprasellar extension and associated with very high morbidity and mortality rates, 4,19,23,53 giant pituitary adenomas are now associated with improved outcomes provided by microsurgical techniques and instrumentation. Giant prolactinomas stand out clinically among this group of giant pituitary tumors, not only in their known frank invasiveness, 1,39 but also in their presumed hyperresponsiveness to pharmocotherapy. 34,37 Although case reports and anecdotal descriptions of giant prolactinomas exist in the surgical literature, there are no published Object. Giant prolactinomas are rare tumors whose treatment and outcome has only been addressed in isolated case reports. The authors document the long-term follow-up findings and clinical outcome in a group of patients with giant prolactinomas.
