Endocrinol Metab.  2012 Mar;27(1):59-62. 10.3803/EnM.2012.27.1.59.

Papillary Thyroid Carcinoma Manifesting as an Autonomously Functioning Thyroid Nodule

• Kim JH
• Na GJ
• Kim KW
• Ko HJ
• Jeon SW
• Kim YJ
• Kim SJ
• Jo HD
• Kim CJ

• KMID: 2134819
• DOI: http://doi.org/10.3803/EnM.2012.27.1.59

Abstract

Hyperfunctioning thyroid carcinoma is very rare. Hence, radionuclide imaging of thyroid hot nodules usually suggests a benign tumor, and less than 4% of cases have been reported as malignant. We would like to present a case of a hyperfunctioning papillary thyroid carcinoma that was initially treated with radioactive iodine. A 58-year-old woman was referred to our hospital for palpable thyroid nodule and a 5-kg weight loss within 6 months. Thyroid function test revealed thyrotoxicosis, and thyroid autoantibodies were absent. 99mTc thyroid scintigraphy showed a 2 x 2 cm-sized hyperactive hot nodule at the left lobe. Despite radioactive iodine treatment with a dose of 10 mCi 131I, thyroid function did not improve. Fine needle aspiration revealed papillary thyroid cancer. The patient underwent total thyroidectomy. Although clinical features and thyroid scans suggest a benign nodule, the possibility of malignancy should not be ruled out. Malignant thyroid hot nodules are rare; however, its possibility should be taken into account. Therefore, we suggest that ruling out malignancy by existing diagnostic guidelines can misdiagnose even a typical case with benign features. As thyroid nodule detection is getting sensitive and accurate, we present this case to discuss whether additional diagnostic approaches would be necessary for thyroid nodules.

Keyword

Thyroid nodule; Papillary thyroid cancer

MeSH Terms

Autoantibodies
Biopsy, Fine-Needle
Carcinoma
Female
Humans
Iodine
Middle Aged
Thyroid Function Tests
Thyroid Gland
Thyroid Neoplasms
Thyroid Nodule
Thyroidectomy
Thyrotoxicosis
Weight Loss
Autoantibodies
Carcinoma
Iodine
Thyroid Neoplasms

Figure

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  Fig. 1 Thyroid 99mTc scintigraphy shows a hot nodule in the left lobe while remaining areas shows minimal activity.

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  Fig. 2 Thyroid ultrasonography reveals a 1.8 × 1.2 × 1.7 cm sized ill-defined hypo echoic nodule in left thyroid lobe.

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  Fig. 3 Histology of the resected thyroid nodule. A. Histology demonstrates the papillary structure with ill defined margin (H&E stain, × 40, thyroid). B. The large hyperchromic nuclei with central core and groove are compatible with papillary thyroid carcinoma (H&E stain, × 400, thyroid).

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  Fig. 4 Gene analysis using real time polymerase chain reaction (PNAClamp B-raf Mutation Detection Kit) presents amplified B-raf mutation like other sample studies. PNA, peptide nucleic acid.

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