Endocrine Abstracts

A 38-year-old woman with chronic autoimmune thyroiditis and hypothyroidism treated with levothyroxine (125 μg/day) was referred to our outpatient clinic with a history of sudden increase of goiter, weakness, dysphagia, dyspnea and suffocating sensation. Physical examination showed an enlarged, stony thyroid gland (three times of normal), without palpable cervical lymph nodes. Biochemical evaluation showed the following abnormalities: TSH 6.0 μU/ml (0.4–4.3), free-T4 11 pg/ml (7–17), free-T3 2.9 pg/ml (2.7–5.7), TgAb >2000 U/ml (<1.0–30), TPOAb >1000 U/ml (<1.0–10) and TSH receptor antibodies <1 UI/l (<2). Thyroid ultrasound showed an enlarged diffusely (VT=109 ml) and hypoechoic gland, with absent vascularization at color-power-Doppler, without cervical lymph nodes. At Computed tomography (CT) was found a hypodense, enlarged thyroid gland (right lobe: 50×30×65 mm, left lobe: 52×27×65 mm, and isthmus 20 mm) with tracheal compression and esophageal dislocation. Fine needle aspiration biopsy was not diagnostic. The patient underwent thyroid biopsy, which showed a T and C lymphocyte infiltration with extensive fibrosis, suggesting the Riedel’s thyroiditis diagnosis. With the aim to support this diagnosis, further, imaging studies were made. Magnetic resonance imaging showed thyroid hypointensity in all pulse sequences with homogeneous enhancement after gadolinium administration; fludeoxyglucose F-18 positron emission tomography (FDG-PET) revealed an abnormal thyroid uptake, indicating an increased glucose metabolism. The dose levothyroxine was increased at 137.5 μg/day to correct hypothyroidism and prednisone (75 mg/day) was started. The prednisone dose was tapered off gradually and withdrawn after seven months. The clinical conditions improved dramatically in few weeks of treatment. At the end of therapy, ultrasound and CT showed a normal thyroid volume (right lobe 20×12 mm and left lobe 21×13 mm), while no uptake of FDG-PETl was found. Six-months after withdrawal prednisone treatment, the patient is in good health.