Background: Riedel thyroiditis (RT) is a rare form of thyroiditis; thus, data about the disease course and treatment options are limited. Therefore, we aimed to assess the clinical, serological, radiological, and histopathological features, as well as short- and long-term follow-up of RT patients under glucocorticoid (GC) and tamoxifen citrate (TMX). Parameters related to IgG4-related diseases (IgG4-RD) were also investigated. Methods: Eight patients with RT diagnosed between 2000 and 2019 were enrolled. Data were collected in a retrospective and prospective manner. The diagnosis was confirmed with histopathological features in all patients. Results of the treatment with GCs on short- to mid-term, followed by TMX in the long term, were evaluated. Results: The mean age at diagnosis was 40.5 ± 6.8 years; female predominance was observed (F/M:7/1). Parameters related to IgG4-RD, like increase in IgG4 serum levels, total plasmablast counts, and IgG4+ plasmablasts, were negative in most of our patients in both active and inactive states of the disease. Likewise, an increased ratio of IgG4/IgG-positive plasma cells >40% could only be observed in 2 cases. GCs followed by TMX were given to the patients with an over-all median follow-up time of 67 (8–216) months. All the patients considerably improved clinically and had a reduction in the size of the mass lesion on GCs, followed by TMX therapy. None of the patients had a recurrence under TMX therapy for a median period of 18.5 (7–96) months. Conclusion: Even though RT is suggested to be a member of IgG4-RD, serologic or histological evidence of IgG4 elevation or positivity is only useful for diagnosis and follow-up of RT. The diagnosis should be based on clinical and radiological evidence and confirmed by histopathology. GCs are effective for initial treatment, and TMX is a successful and safe therapeutic option for long-term maintenance therapy.

Background: The optimal therapeutic choice for Graves' hyperthyroidism in the presence of moderate-severe Graves' orbitopathy (GO) remains controversial. Objectives: We aimed to compare GO course in patients with moderate-severe GO treated with early total thyroidectomy (TTx) versus antithyroid drug (ATD) regimens, in a prospective, randomized manner. Methods: Forty-two patients with moderate-severe GO were enrolled. A total of 4.5 g of pulse corticosteroids were given intravenously to all patients before randomization. Patients in the first group were given TTx, whereas patients in the second group were treated with ATDs. TSH was kept between 0.4 and 1 mIU/l. The clinical course of GO was evaluated with proptosis, lid aperture, clinical activity score (CAS), and diplopia. Results: Eighteen and 24 patients were randomized to the TTx and ATD groups, respectively. Thyroid autoantibodies decreased significantly, and there were significant improvements in proptosis, lid aperture, and CAS in the TTx group. While in the ATD group the decrement in thyroid autoantibodies was not significant, there were significant improvements in proptosis and CAS. When the TTx group was compared with the ATD group, anti-TPO, anti-Tg, and TSH-receptor antibodies were significantly decreased in the TTx group (p < 0.01), but there was no significant difference with respect to proptosis, lid aperture, CAS, and diplopia between the two groups during a median (min.-max.) follow-up period of 60 months (36-72). Conclusion: Although no definitive conclusions could be drawn from the study, mainly due to limited power, early TTx and the ATD treatment regimens, followed by intravenous pulse corticosteroid therapy, seemed to be equally effective on the course of GO in this relatively small group of patients with moderate-severe GO during a median (min.-max.) follow-up period of 60 months (36-72).