title: Rapid re-expansion of a macroprolactinoma after early discontinuation of bromocriptine.
abstract: Prolactin (PRL)-secreting pituitary adenomas are the most common functioning pituitary tumors. Medical treatment with dopamine agonists is the therapy of choice for macroprolactinomas (> or = 10 mm). Withdrawal of bromocriptine after weeks or months of uninterrupted therapy has been associated with rapid tumor re-expansion as evidenced by x-ray and CT scanning of the pituitary region. We report a patient with a giant macroprolactinoma who had a dramatic response to bromocriptine (tumor volume shrinkage of 53% within a month) but rapid re-expansion to its original dimensions one week after discontinuation of bromocriptine. To our knowledge, this is the first time that the rapid shrinkage/re-expansion of a macroprolactinoma has been documented with serial MRI scans.
authors.affiliation: Pituitary and Neuroendocrine Center, Section of Neurosurgery, Department of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Orrego
authors.forename: W F
authors.initials: WF
authors.lastname: Chandler
authors.forename: A L
authors.initials: AL
authors.lastname: Barkan
mesh_terms: D000328:Adult; D001971:Bromocriptine / Q000008:administration & dosage* / Q000627:therapeutic use; D018491:Dopamine Agonists / Q000008:administration & dosage* / Q000627:therapeutic use; D004334:Drug Administration Schedule; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010911:Pituitary Neoplasms / Q000175:diagnosis / Q000188:drug therapy*; D015175:Prolactinoma / Q000175:diagnosis / Q000188:drug therapy*; D013997:Time Factors
chemical_list: D018491:Dopamine Agonists; D001971:Bromocriptine