title: Spurious t3 thyrotoxicosis unmasking multiple myeloma.
abstract: Objective. To document a case of spurious T3 thyrotoxicosis in a 54-year-old woman. Methods. We present the diagnostic approach of a patient with euthyroid hypertri-iodothyronemia. Results. A 54-year-old, clinically euthyroid woman without personal or family history of thyroid disease referred to endocrinology for possible T3 thyrotoxicosis, after thyroid function tests revealed total T3 > 800 ng/dL (reference range 60-181), normal TSH, and T4. The laboratory data were not compatible with the clinical picture, so thyroid binding globulin abnormalities were suspected. Additional laboratory studies confirmed the diagnosis of multiple myeloma. Conclusion. Monoclonal gammopathy is characterized by the presence of a monoclonal immunoglobulin in the serum or urine, occurring in multiple myeloma, and can cause assay interference and spurious results. We identify a newly recognized cause of euthyroid hypertri-iodothyronemia, due to binding of T3 to monoclonal immunoglobulins in the setting of multiple myeloma. Our case is the only one to date suggesting that monoclonal immunoglobulins from multiple myeloma may exhibit binding to T3 only.
authors: SUNY Downstate Medical Center, Department of Endocrinology, 450 Clarkson Avenue, Box 1205, Brooklyn, NY 11203, USA.
authors: Marianna
authors: M
authors: Antonopoulou
authors: Arnold
authors: A
authors: Silverberg
references: J Clin Endocrinol Metab. 1982 May;54(5):1045-50
references: 6801074
references: N Engl J Med. 1977 Nov 10;297(19):1068-9
references: 909555
references: Am J Med. 1983 Apr;74(4):564-9
references: 6404165
references: Clin Chem. 1993 Aug;39(8):1739-42
references: 8353966
references: Clin Chim Acta. 1990 Feb 28;187(2):141-8
references: 2107988
references: Clin Chim Acta. 1982 Feb 5;118(2-3):293-301
references: 7055987
references: Endocr Rev. 1989 Aug;10(3):275-93
references: 2506004
references: Clin Endocrinol (Oxf). 1994 Sep;41(3):365-70
references: 7955443
references: J Clin Endocrinol Metab. 1969 Jul;29(7):957-61
references: 4978385
references: J Clin Oncol. 1995 Apr;13(4):854-7
references: 7707111
references: Clin Chim Acta. 1988 Dec 15;178(2):171-80
references: 3149557
references: J Clin Endocrinol Metab. 1983 May;56(5):1009-15
references: 6300171
references: Ann Intern Med. 1974 Feb;80(2):194-9
references: 4204545
references: J Clin Endocrinol Metab. 1990 Sep;71(3):764-9
references: 2394778
references: Clin Endocrinol (Oxf). 1978 Feb;8(2):133-9
references: 580230
references: Lancet. 1976 Apr 17;1(7964):866-7
references: 56692