Misdiagnosis due to the hook effect in prolactin assay.


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Yener S., Comlekci A., Arda N., MEN S., Yesil S.

Medical principles and practice : international journal of the Kuwait University, Health Science Centre, cilt.17, sa.5, ss.429-31, 2008 (SCI-Expanded) identifier identifier identifier

Özet

Objectives: To describe a patient who was misdiagnosed as having a nonfunctional pituitary tumor due to the hook effect on prolactin measurements. Clinical Presentation and Intervention: A 45-year-old female was admitted with visual disturbances, panhypopituitarism and central diabetes insipidus due to pituitary tumor recurrence. She had been operated 4 times earlier and received cranial irradiation for a suspected nonfunctional pituitary adenoma. Serum prolactin was moderately elevated (164.5 ng/ml), but increased markedly after 1: 100 dilution to 14,640 ng/ml. Diagnosis of a giant macroprolactinoma was made and cabergoline was started. Prolactin level normalized and a mild shrinkage of the tumor was achieved after 12 months of therapy. Conclusion: The hook effect must be kept in mind while evaluating a giant pituitary adenoma with moderately elevated prolactin levels. This way unnecessary surgical procedures or irradiation may be avoided. Copyright (c) 2008 S. Karger AG, Basel.