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Case Reports in Endocrinology
Volume 2012 (2012), Article ID 280319, 4 pages
http://dx.doi.org/10.1155/2012/280319
Case Report

Thyroglobulin Gene Mutation with Cold Nodule on Thyroid Scintigraphy

1Department of Internal Medicine, Toyama Prefectural Central Hospital, 2-2-78 Nishinagae, Toyama, Toyama 930-8550, Japan
2Department of Pediatrics, Toyama Prefectural Central Hospital, 2-2-78 Nishinagae, Toyama, Toyama 930-8550, Japan
3Department of Clinical Laboratory Medicine, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Shimotsuga, Tochigi 321-0293, Japan
4Department of Clinical Pathology, Toyama Prefectural Central Hospital, 2-2-78 Nishinagae, Toyama, Toyama 930-8550, Japan
5Department of Thoracic Surgery, Toyama Prefectural Central Hospital, 2-2-78 Nishinagae, Toyama, Toyama 930-8550, Japan
6Department of Radiology, Toyama Prefectural Central Hospital, 2-2-78 Nishinagae, Toyama, Toyama 930-8550, Japan

Received 12 January 2012; Accepted 19 February 2012

Academic Editors: T. GrĂ¼ning and N. Islam

Copyright © 2012 Toshio Kahara et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Thyroglobulin gene mutation is a rare cause of congenital hypothyroidism, but thyroglobulin gene mutations are thought to be associated with thyroid cancer development. A 21-year-old Japanese man treated with levothyroxine for congenital hypothyroidism had an enlarged thyroid gland with undetectable serum thyroglobulin despite elevated serum TSH level. The patient was diagnosed with thyroglobulin gene mutation, with compound heterozygosity for Gly304Cys missense mutation and Arg432X nonsense mutation. Ultrasonography showed a hypovascular large tumor in the left lobe that appeared as a cold nodule on thyroid scintigraphy. He underwent total thyroidectomy, but pathological study did not reveal findings of thyroid carcinoma, but rather a hyperplastic nodule with hemorrhage. Strong cytoplasmic thyroglobulin immunostaining was observed, but sodium iodide symporter immunostaining was hardly detected in the hyperplastic nodule. The clinical characteristics of patients with thyroglobulin gene mutations are diverse, and some patients are diagnosed by chance on examination of goiter in adults. The presence of thyroid tumors that appear as cold nodules on thyroid scintigraphy should consider the potential for thyroid carcinoma, if the patient has relatively low serum thyroglobulin concentration in relation to the degree of TSH without thyroglobulin autoantibody.