452 ENDOCRINE PRACTICE Vol 14 No. 4 May/June 2008 Original Article POOR CORRElATION Of SERuM α-SubuNIT CONCENTRATION AND MAgNETIC RESONANCE IMAgINg fOllOwINg PITuITARy SuRgERy IN PATIENTS wITh NONfuNCTIONAl PITuITARy MACROADENOMAS Maria M. Pineyro, MD, 1 Antoine Makdissi, MD, FACE, 1 Charles Faiman, MD, MACE, 1 Richard A. Prayson, MD, 2 Sethu K. Reddy, MD, MBA, FACP, MACE, 1 Marc C. Mayberg, MD, 3 Robert J. Weil, MD, 4 and Amir H. Hamrahian, MD, FACE 1 Submitted for publication August 4, 2007 Accepted for publication November 9, 2007 From the 1 Department of Endocrinology, Diabetes, and Metabolism and 2 Department of Anatomic Pathology, Cleveland Clinic, Cleveland, Ohio, 3 Seattle Neuroscience Institute, Seattle, Washington, and 4 Brain Tumor and Neuro-Oncology Center, Cleveland Clinic, Cleveland, Ohio. Address correspondence and reprint requests to Dr. Amir H. Hamrahian, Department of Endocrinology, Diabetes, and Metabolism, Cleveland Clinic, 9500 Euclid Avenue, Desk A53, Cleveland, OH 44195. E-mail: hamraha@ccf. org. © 2008 AACE. ABSTRACT Objective: To review the clinical utility of measuring serum α-subunit as a marker for residual tumor in a group of patients with surgically resected nonfunctional pituitary adenomas. Methods: In this retrospective cross-sectional chart review using the pituitary database at the Cleveland Clinic, we identifed patients with nonfunctional pituitary mac- roadenomas over a 4-year period (2000-2004) and selected those patients who had an elevated α-subunit concentration measured before pituitary surgery. Presurgery and post- surgery measurements of α-subunit, luteinizing hormone, follicle-stimulating hormone, and thyroid-stimulating hor- mone were documented. Findings from preoperative and postoperative pituitary magnetic resonance imaging (MRI) were reviewed. Results: We identifed 54 patients who were evalu- ated for nonfunctional pituitary macroadenomas during the study period. Of the 39 who underwent pituitary surgery, 34 had a serum α-subunit concentration measured before surgery. Eight of 34 patients had elevated preoperative α- subunit levels with a median value of 1.8 ng/mL (range, 1.0-3.4 ng/mL). Of the 8 patients, 7 had follow-up MRI a median of 12 months (range, 6-52 months) after surgery. One patient was lost to follow-up. Three of 7 patients had persistently elevated α-subunit levels postoperatively; in 2 of these 3, MRI did not identify residual tumor. Among the 4 patients with postoperative normalization of α-subunit, 2 patients had residual tumor on MRI. Conclusion: The discrepancy between α-subunit lev- els and postoperative MRI calls into question the value of routine α-subunit measurement as a tumor marker in patients with nonfunctional pituitary macroadenomas. (Endocr Pract. 2008;14:452-457) Abbreviations: FSH = follicle-stimulating hormone; LH = luteinizing hormone; MRI = magnetic resonance imaging; TSH = thyroid-stimulating hormone INTRODUCTION The α-subunit is common to the glycoprotein hormones luteinizing hormone (LH), follicle-stimulating hormone (FSH), thyroid-stimulating hormone (TSH), and human chorionic gonadotropin. It is secreted as a free molecule in physiologic states (1) and in increased amounts in states of increased TSH or gonadotropin secretion such as primary hypothyroidism, primary hypogonadism, and pregnancy. In addition, pituitary tumors may secrete α-subunit alone or in association with other pituitary hormones including TSH, gonadotropins, growth hormone, prolactin, and cor- ticotropin (2-4). It is a common practice to measure serum α-subunit routinely in patients with nonfunctional pituitary adeno- mas. However, there are limited data regarding the util- ity of α-subunit as a tumor marker either for predicting operative cure or tumor recurrence. In the present study, we evaluated the clinical utility of α-subunit determination in patients with surgically removed nonfunctional pituitary macroadenomas. PATIENTS AND METHODS This case series was extracted from the Cleveland Clinic pituitary database and was approved by the institu- tional review board of the Cleveland Clinic.