Riedel’s Thyroiditis Mimicking as Anaplastic Thyroid Carcinoma: Unusual Presentation

Abstract

Riedel's thyroiditis is a rare inflammatory process which not only involves thyroid gland but also the surrounding vital structures. It may also be associated with various forms of systemic fibrotic disorders. The exact etiology is not known, but currently most favored view is that of a localized form of systemic fibrotic process. We report a case of Riedel's thyroiditis in a patient, highlighting a rare presentation mimicking anaplastic carcinoma. Clinical awareness of such presentation of Riedel's thyroiditis would enhance our ability to make this diagnosis promptly. Apart from avoiding or minimizing aggressive surgical intervention, awareness of such clinical entity may avoid complications and hence morbidity. Our case also highlights the difficulty in histological diagnosis which is very important to rule out malignancy and avoiding any major surgical intervention fraught with complications. Good response to high dose steroids as seen in our case is the current accepted treatment of choice.

Riedel’s Thyroiditis: Pitfalls in Diagnosis and Subsequent Complications

“…Some of the signs and symptoms of Riedel's thyroiditis overlap with those of other thyroid disorders [ 7 ]. In particular, the clinical presentation of Riedel's thyroiditis is often said to mimic malignancy [ 8 ], mainly anaplastic carcinoma [ 9 , 10 ]. Misdiagnosis with closely resembling diseases can also contribute to the impediment of reaching the correct diagnosis.…”

Thyroid Nodules and Biopsy

“…Rarely, a nodule may bleed internally or undergo sudden enlargement, stretching the thyroid capsule and skin, leading to pain and sensitivity [19,39]. Rapid and painful growth should raise concerns for aggressive conditions such as anaplastic thyroid cancer, Riedel's thyroiditis, or primary thyroid lymphoma [40,41]. The patient history should include age, gender, body mass index (BMI), presence of metabolic syndrome, personal or family history of thyroid disease or cancer, associated syndromes such as Familial medullary thyroid cancer, endocrine neoplasia, Cowden syndrome, Carney complex, Werner syndrome, Familial adenomatous polyposis, DICER1 syndrome, previous imaging and biopsies, history of acromegaly, exposure to head or neck radiation, the growth rate of the neck mass, anterior neck pain, symptoms of dysphonia, dysphagia or dyspnea, signs of hyperthyroidism or hypothyroidism, use of iodine-containing medications or supplements, tobacco use, and stress [42].…”

IgG4-related sclerosing thyroiditis (Riedel-Struma): a review of clinicopathological features and management

“…Fibrosis of the parathyroid glands and ensuing hypoparathyroidism occur less frequently. About one-third of patients with RT suffer from ailments related to fibrosis in retroperitoneum/pancreas, mediastinum, lungs, lacrimal glands, orbit, salivary glands, and gallbladder [ 1 , 7 , 19 , 39 , 50 – 57 , 59 – 70 , 72 , 73 ].…”

“…Standard dosages are 100 mg of prednisone daily [ 5 ]. Administration can start with lower doses (from 15 to 60 mg) and even stay at these if the response is satisfactory [ 9 – 13 , 15 , 18 , 19 , 24 , 27 , 31 , 33 , 36 , 43 , 44 , 46 – 49 , 78 , 79 , 94 , 96 , 99 ]. In the case of smokers, the dose should be increased and the therapy repeated [ 7 ].…”

“…Currently, no acute overdose of tamoxifen has been observed [ 10 , 11 , 15 , 18 , 19 , 24 , 31 , 43 , 45 , 47 , 78 , 97 , 107 – 110 ]. It is noted that tamoxifen is used in other inflammatory conditions related to multifocal fibrosis [ 108 ].…”