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Kalman Kovacs, Lucia Stefaneanu, Eva Horvath, Michael Buchfelder, Rudolph Fahlbusch and Wolfgang Becker

known. To obtain more insight into dopamine agonist resistance, we used several morphological techniques to investigate a prolactin-producing pituitary tumor surgically removed from a 14-year-old girl who did not respond to oral bromocriptine or CV 205–502, two dopamine agonist drugs. The present report describes the findings we obtained using histology, immunocytochemistry, electron microscopy, and in situ hybridization. Case Report Examination This 14-year-old girl presented with a sports-related minor head trauma. An enlarged sella turcica was noted

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Raj K. Shrivastava, Marc S. Arginteanu, Wesley A. King and Kalmon D. Post

posttreatment prolactin levels are the best indicator of success, 14, 49 these values are only obtained after a necessary trial period, which can last up to 6 weeks. Enthusiasm regarding the sensitivity of prolactinomas to dopamine agonist therapy should not obscure the fact that the mechanisms of dopamine agonist resistance are still not understood, and that these treatment failures cannot be determined before deciding on the best therapy for the patient. Giant Prolactinoma Size Does Not Correlate With Prolactin Level Despite previously published reports on the

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Michael C. Oh and Manish K. Aghi

higher percentage of patients with prolactinomas do not respond to dopamine agonists through a reduction in tumor size. When dopamine agonists fail to induce endocrine and radiographic remission of a prolactinoma, transsphenoidal surgery or radiosurgery is available, as are some unconventional medical therapies. Recent studies have better defined the characteristics and mechanisms of dopamine agonist resistance in prolactinomas, which will enable better identification of appropriate treatments. Here, we define the phenomenon of resistance to dopamine agonist therapy in

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Alexander Micko, Arthur Hosmann, Aygül Wurzer, Svenja Maschke, Wolfgang Marik, Engelbert Knosp and Stefan Wolfsberger

with dopamine agonist resistance. Besides the thin osseous sellar floor, the C 3 segment of the right ICA does not show bony covering on advanced protocol ( A , axial) and intraoperatively ( B ), important for anticipating when opening the sellar floor. Conversely, a patient is seen with a microadenoma with solid bone covering the ICA seen on image guidance ( C , axial). Asterisks denote the uncovered ICA. CP = carotid protuberance; MS = median septum; SF = sellar floor. Figure is available in color online only. Complications We assessed the impact of the advanced

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Yi-Chieh Hung, Cheng-Chia Lee, Huai-che Yang, Nasser Mohammed, Kathryn N. Kearns, Ahmed M. Nabeel, Khaled Abdel Karim, Reem M. Emad Eldin, Amr M. N. El-Shehaby, Wael A. Reda, Sameh R. Tawadros, Roman Liscak, Jana Jezkova, L. Dade Lunsford, Hideyuki Kano, Nathaniel D. Sisterson, Roberto Martínez Álvarez, Nuria E. Martínez Moreno, Douglas Kondziolka, John G. Golfinos, Inga Grills, Andrew Thompson, Hamid Borghei-Razavi, Tanmoy Kumar Maiti, Gene H. Barnett, James McInerney, Brad E. Zacharia, Zhiyuan Xu and Jason P. Sheehan

decrease in the PRL level or overall tumor size in response to standard doses of dopamine agonists. 30 Dopamine agonist resistance is identified by an inability to lower PRL levels to within the normal range and a failure to reduce tumor size by 50% despite administration of the maximally tolerated dose. 11 , 15 , 29 , 30 Macroadenomas are more likely than microadenomas to be refractory to dopamine agonist treatment, and male patients show an increased resistance compared to their female counterparts. 10 , 31 The proposed strategy of medical treatment for a dopamine