Graves’ Disease after Unilateral Riedel’s Thyroiditis

Abstract

Riedel’s thyroiditis, also termed “invasive fibrous thyroiditis,” is the rarest form of autoimmune thyroiditis and can be associated with systemic fibrotic processes, Hashimoto thyroiditis (1, 2), and Graves’ disease (3). A case of hyperthyroidism followed by spontaneous hypothyroidism and Riedel’s thyroiditis has been reported (4). Two previously reported patients from our institution had invasive fibrous thyroiditis that evolved from antecedent Graves’ disease, as indicated by thyroid dysfunction, bilateral ophthalmopathy, and positive TSH receptor-stimulating autoantibodies (5). We present a new case. In 2004, a 26-yr-old woman presented with a mass in the left thyroid lobe, pain, and respiratory distress. Thyroid function was normal. A tracheostomy and biopsy showed Riedel’s thyroiditis. Therapy with corticosteroids and tamoxifen stabilized the disease. After 1 yr, the tracheostomy was closed. In 2008, her TSH level was less than 0.01 mIU/liter, her free T4 was 4.5 ng/dl (58 pmol/liter; normal, 0.8 –1.8 ng/dl or 10 –23 pmol/ liter), and her serum was strongly positive for TSH receptor antibodies (52%; normal, 16%). The diagnosis of Graves’ hyperthyroidism was made. Her 24-h iodine131 uptake was 33% (upper limit of normal, 29%). She was treated with 19.7 mCi iodine-131. Computed tomography of the neck, performed in 2004 and 2008, showed left lobe thyroid enlargement and compression of the trachea (Fig. 1). Ultrasonography of the thyroid in 2008 (Fig. 2) showed hypervascularity in the areas not affected by Riedel’s thyroiditis; the absence of vascularity in the hypoechoic areas of the left lobe corresponded to Riedel’s involvement, as shown by computed tomography. The present case is of interest because Graves’ disease developed after 3 yr of stability of Riedel’s thyroiditis. In this case, the fibrotic process with extra thyroidal extension was unilateral. Graves’ hyperthyroidism developed in the uninvolved areas of the thyroid. This case and similar reported cases support the notion of autoimmune ISSN Print 0021-972X ISSN Online 1945-7197 Printed in U.S.A. Copyright © 2010 by The Endocrine Society doi: 10.1210/jc.2009-2609 Received December 8, 2009. Accepted April 16, 2010. FIG. 1. Computed tomographic images of the neck. A, Image taken with contrast (2004). Note partial involvement of the left lobe with fibrosis (F), extrathyroidal extension, and significant tracheal narrowing (black arrow) and engulfment of the common carotid artery (white arrow). Also note the uninvolved part of left lobe (L). The right lobe of the thyroid (R) is completely uninvolved. B, Image taken without contrast (2008). Note the stability and partial resolution of the process in the left lobe. (F denotes partially resolved left lobe fibrosis; L, uninvolved part of the left thyroid lobe; R, right lobe. The black arrow shows improved tracheal narrowing.) S P E C I A L F E A T U R E