The Journal of Clinical Endocrinology & Metabolism Vol. 92, No. 6 2005-2006
Copyright © 2007 by The Endocrine Society
Riedel’s Thyroiditis Occurring in a Multinodular Goiter, Mimicking Thyroid Cancer
Marijke Annaert,
Marleen Thijs,
Raf Sciot and
Brigitte Decallonne
Departments of Endocrinology (M.A., B.D.), Radiology (M.T.), and Pathology (R.S.), University Hospital Gasthuisberg, 3000 Leuven, Belgium
Address all correspondence and requests for reprints to: B. Decallonne, University Hospital Gasthuisberg, Herestraat 49, 3000 Leuven, Belgium. E-mail: brigitte.decallonne{at}med.kuleuven.be.
A 52-yr-old female with multinodular goiter with benign fine-needle aspiration (FNA) cytology presented with progressive compressive symptoms. Clinically, the left lobe was enlarged, painless, but firm. Serum TSH and calcitonin were normal, and thyroglobulin was elevated. C-reactive protein and leukocyte counts were normal. Thyroid-related autoantibodies (thyroid peroxidase, thyroglobulin, and TSH receptor) were absent. The ultrasound performed 1 yr before showed hyperechoic nodules (Fig. 1A
). Now, the volume of the left lobe increased nearly 2-fold due to hypoechoic, hypovascular tissue surrounding the hyperechoic nodules (Fig. 1B). During FNA, the hypoechoic tissue felt remarkably harder than the hyperechoic nodules. Cytology of the nodules was confirmed to be benign. However, cytology of the hypoechoic part showed a small amount of follicular epithelial cells with enlarged, irregular nuclei and no colloid. Based on the inconclusive cytology, the absence of biochemical abnormalities, and the increasing mechanical complaints, a total thyroidectomy was performed. During surgery, a white stony-hard left thyroid lobe was disclosed. Histopathologic examination showed a sclerotic mass, consisting of spindle-shaped cells and mononuclear inflammatory cells, infiltrating the follicular adenomas (Fig. 2), leading to the diagnosis of Riedel’s thyroiditis. This is a rare fibrosclerotic infiltrative thyroid disorder of unclear etiology, during which normal thyroid tissue is replaced by fibrous tissue, hypoechoic and hypovascular on ultrasound (2, 3), often expanding outside the thyroid capsule, and sometimes part of multifocal (retroperitoneal, retroorbital, and mediastinal) fibrosclerosis (1, 2, 3). The main differential diagnosis is invasive thyroid cancer. FNA often fails to distinguish between these two entities, and the diagnosis can be complicated further in an already nodular thyroid.
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FIG. 1. A, Sagittal longitudinal view of the left thyroid lobe (3-dimensional diameters, 26 x 26 x 47 mm), containing three hyperechoic nodules (arrows). B, Sagittal longitudinal view of the same left lobe 15 months later, clearly enlarged (3-dimensional diameters 32 x 31 x 55 mm) and characterized by a hypoechoic aspect (arrow) contrasting with the inlaying hyperechoic nodules.
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FIG. 2. Low-power view, showing the infiltrative nature of the fibroinflammatory process (left), which extends into the follicles of the adenoma (right). Hematoxylin and eosin staining.
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Footnotes
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Disclosure Statement: The authors have nothing to disclose.
Abbreviation: FNA, Fine-needle aspiration.
Received January 11, 2007.
Accepted March 12, 2007.
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References
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- Schwaegerle SM, MacConahey WM, Beahrs OH 1988 Riedel’s thyroiditis. Am J Clin Pathol 90:715–722[Medline]
- Papi G, Corrado S, Cesinaro AM, Novelli L, Smerieri A, Carapezzi C 2002 Riedel’s thyroiditis: clinical, pathological and imaging features. Int J Clin Practice 56:65–67
- Fontaine S, Gaches F, Lamant L, Uzan M, Bennet A, Caron PH 2005 An unusual form of Riedel’s thyroiditis: a case report and review of the literature. Thyroid 15:85–88[CrossRef][Medline]
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