Invasive Giant Prolactinoma with Loss of Therapeutic Response to Cabergoline: Expression of Angiogenic Markers

The present study reports the case of a 70-year-old Caucasian man who was referred to the Military Hospital of Buenos Aires for evaluation of a giant sellar-extrasellar mass with extension in the right temporal lobe and compression of the third ventricle. Patient was initially responsive to cabergoline with reduction of prolactin levels and shrinkage of tumor burden for at least 36 months. Thereafter, prolactin levels and tumor size increased even though cabergoline dosage was increased. Transcraneal surgery was performed at 56 months of treatment. Prolactin levels and tumor proliferation did not subside and the patient died 14 months later. High GH and IGF-I levels were observed in the late stages of tumor development, with no evidence of acromegalic features. Immunohistochemistry of the excised tumor revealed strong immunoreactivity for VEGF and FGF-2, two potent angiogenic factors, and CD31 (an endothelial marker) indicating high vascularization of the adenoma.