Shahi et al. Journal of Medical Case Reports 2010, 4:15 http://www.jmedicalcasereports.com/content/4/1/15 Page 2 of 3 Figure 1 Computed tomography (CT) scan of the neck and the thoracic outlet. This shows a large thyroid mass predominantly affecting the right lobe of the thyroid gland. The trachea has been pushed over to the left. wedge biopsy was taken to establish histological diagno- sis. Histopathology showed an admixture of fibrous tis- sue with focal collagen hyalinization and inflammatory infiltrate rich in lymphocytes and plasma cells. Occa- sional giant cells were present with atrophic thyroid fol- licles. At this stage, the diagnosis was confirmed as Riedel’s thyroiditis, based on the histology results. The patient was subsequently started on 80 mg/day of pre- dnisolone. After four weeks, there was marked improve- ment in the voice and swallowing of the patient with reduction in the size of the goitre. Within two weeks of starting steroids, the ESR was noted to have fallen to 10 mm/hr. Prednisolone was gradually tapered over 10 months to a dose of 5 mg on alternate days. Repeat CT scan confirmed reduction in the size of the goitre with minimal shift in the trachea (Figure 2). Discussion The origin of Riedel’s thyroiditis remains unknown, although several theories have been proposed. It may be seen as isolated or as part of multifocal fibrosclerosis. In 1922, Ewing stated that Riedel’s thyroiditis is a variant of De Quervain’s thyroiditis [3]. At one time, it was thought to be an advanced stage of Hashimoto’s disease, collagen vascular disorder or an autoimmune disease. Familial occurrence of multiple fibrosclerotic lesions, which include Riedel’s thyroiditis, have been reported and have suggested a genetically determined process [4]. The clinical picture of Riedel’s thyroiditis is nonspeci- fic and its major clinical significance lies in its ability to Figure 2 Computed tomography (CT) scan of the neck and thoracic outlet. Repeat CT scanning after ten months of steroid therapy confirms reduction in size of the goitre and with return of the trachea to midline position. mimic invasive thyroid carcinoma [5]. Most patients present with non-painful, non-tender goitre that may appear gradually or suddenly and may produce pressure symptoms such as dyspnea and dysphagia in addition to hoarseness with vocal cord paralysis. However, cervical lymphadenopathy is not present. Our patient was unu- sual in that his goitre was painful and tender although the rest of the clinical picture was typical. Laboratory findings in Riedel’s thyroiditis are nonspe- cific. The ESR is frequently elevated. In our patient, ESR was elevated and normalized within two weeks of ster- oid therapy. Antithyroid antibodies may or may not be positive. In one review, antithyroid antibodies were found in 67% of patients [5]. Antithyroid peroxidase antibodies were negative which is against Hashimoto’s thyroiditis. The diagnosis of Riedel’s thyroiditis is not possible with fine-needle aspiration because the dense fibrosis precludes adequate aspiration of the gland. Furthermore, the fibrotic reaction can be difficult to dis- tinguish from that surrounding an undifferentiated car- cinoma [1]. Surgical intervention is done mainly to establish the diagnosis, exclude malignancy and relieve tracheal com- pression. Wedge resection of the thyroid isthmus is often adequate to meet both needs. Extensive resection may be difficult due to fibrosis, increasing the risk of injury of vital neck structures such as recurrent laryn- geal nerve and carotid artery [6].