A L Barkan1, W F Chandler. 1. Pituitary and Neuroendocrine Center, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109-0354, USA.
Abstract
OBJECTIVE AND IMPORTANCE: We present a case of a giant prolactinoma with a falsely low serum prolactin concentration determined by a two-site chemiluminometric assay. Awareness of the possibility of the "high-dose hook effect" in such cases will prevent preoperative misdiagnosis. CLINICAL PRESENTATION: A patient with a giant invasive pituitary tumor was found preoperatively to have serum prolactin of 31 ng/ml. Pathological examination of the excised tissue, however, demonstrated strong staining for prolactin. INTERVENTION: Serial dilutions of the serum disclosed hyperprolactinemia of 280,000 ng/ml, establishing the presence of the "high-dose hook effect." Treatment with pergolide (Permax; Athena Neurosciences, S. San Francisco, CA) decreased tumor size and lowered serum prolactin by more than 99%. CONCLUSION: A "high-dose hook effect" needs to be suspected in every patient with a giant pituitary adenoma (>3 cm) and normal serum prolactin. Subsequently assaying the diluted serum will reliably disclose this phenomenon and allow correct diagnosis and therapy.
OBJECTIVE AND IMPORTANCE: We present a case of a giant prolactinoma with a falsely low serum prolactin concentration determined by a two-site chemiluminometric assay. Awareness of the possibility of the "high-dose hook effect" in such cases will prevent preoperative misdiagnosis. CLINICAL PRESENTATION: A patient with a giant invasive pituitary tumor was found preoperatively to have serum prolactin of 31 ng/ml. Pathological examination of the excised tissue, however, demonstrated strong staining for prolactin. INTERVENTION: Serial dilutions of the serum disclosed hyperprolactinemia of 280,000 ng/ml, establishing the presence of the "high-dose hook effect." Treatment with pergolide (Permax; Athena Neurosciences, S. San Francisco, CA) decreased tumor size and lowered serum prolactin by more than 99%. CONCLUSION: A "high-dose hook effect" needs to be suspected in every patient with a giant pituitary adenoma (>3 cm) and normal serum prolactin. Subsequently assaying the diluted serum will reliably disclose this phenomenon and allow correct diagnosis and therapy.
Authors: Avital Perry; Christopher Salvatore Graffeo; Christopher Marcellino; Bruce E Pollock; Nicholas M Wetjen; Fredric B Meyer Journal: J Neurol Surg B Skull Base Date: 2018-01-24
Authors: Felice Esposito; Daniel F Kelly; Harry V Vinters; Antonio A F DeSalles; Joel Sercarz; Alessandra A Gorgulhos Journal: J Neurooncol Date: 2006-02 Impact factor: 4.130
Authors: Maria Fleseriu; Michael Lee; Maria M Pineyro; Mario Skugor; Sethu K Reddy; Elias S Siraj; Amir H Hamrahian Journal: J Neurooncol Date: 2006-04-06 Impact factor: 4.130
Authors: Christof Schöfl; Beate Schöfl-Siegert; Johann Hinrich Karstens; Michael Bremer; Thomas Lenarz; Jose Sebastian Fernandez Cuarezma; Madjid Samii; Alexander von zur Mühlen; Georg Brabant Journal: Pituitary Date: 2002 Impact factor: 4.107