Riedel Thyroiditis in a Patient with Graves Disease
Mrs. Kim, age 57.\nRecently enlarging neck mass and hoarseness that started 5 days before admission to the hospital.\nA 57-year-old woman visited the outpatient clinic with a very hard, fixed lump that had been present on the right side of her neck for months and hoarseness, which started 5 days previous. The patient had previously taken antithyroid agents prescribed by a private hospital but did not undergo additional tests or follow-up related to her hyperthyroidism. She did not show any symptoms associated with thyrotoxicosis on admission.\nShe underwent intermittent treatment for hyperthyroidism over the last three decades. She has had no other symptoms.\nNo medical problems.\nThe patient was conscious and in no acute distress. She was medically stable with a blood pressure of 130/90 mm Hg, pulse of 76 beats per minute, respiration rate of 20 breaths per minute, and a temperature of 36.5℃. Globe protrusion, scleral icterus, and conjunctival anemia were not observed. Enlarged cervical lymph nodes and jugular vein engorgement were also not present. A hard and fixed thyroid nodule that measured approximately 5×4 cm was palpated, but no neck tenderness was appreciated (). On auscultation, normal heart and breath sounds were observed. Physical examination revealed no pitting edema in her extremities.\nComplete blood count revealed a white blood cell count of 6,460/mm3 (neutrophil 57.4%, lymphocyte 36.6%, monocyte 7.7%, eosinophil 0.6%), hemoglobin of 11.6 g/dL, hematocrit of 35.2%, and platelet count of 295×103/mm3. Urine test was normal. Serum biochemical examination revealed a blood urea nitrogen/creatinine of 25/0.6 mg/dL, total protein/albumin of 7.4/4.3 g/dL, aspartate aminotransferase/alanine aminotransferase of 22/20 IU/L, Na/K/Cl of 142/5.1/105 mEq/L, Ca of 4.6 mEq/L (normal range, 4.5 to 5.2), erythrocyte sedimentation rate of 19 mm/hr, and C-reactive protein <0.2 mg/day. Thyroid function tests revealed thyroid stimulation hormone of 0.07 µIU/mL (normal range, 0.4 to 4.5), free T4 of 3.86 ng/dL (normal range, 0.7 to 2), TBII of 51% (normal range, 0 to 15), thyroglobulin of 493 ng/dL (normal range, 2 to 60), antithyroid microsomal antibody of 3.1 U/mL (normal range, 0 to 8), and negative thyroglobulin antibody of 22 U/mL (normal range, 0 to 55), consistent with Graves disease.\nNormal sinus rhythm.\nSigns of emphysema and right to left shift of the trachea as a consequence of the thyroid nodule.\nA well-defined irregular and hypoechoic nodule measuring 4 cm in diameter, along with large scattered dense calcifications, was observed in the right thyroid lobe (). However, enlarged cervical lymph nodes and invasion into the parathyroid glands were not present.\nSince repeated nonaspiration technique failed to obtain a specimen, we employed an aspiration technique which yielded a very small amount of cytologic specimen. In cytopathologic examination, no malignant cells were detected, but adenomatous goiter was suspected. Although thyroid cancer was not diagnosed by FNA, the large, solid mass and paralyzed vocal cords on the right side suggested the possibility of thyroid cancer. Therefore, a surgical approach was determined for histological diagnosis and treatment.\nThere was a 4.3×4.0 cm nodular lesion occupying most of the right lobe of the thyroid. A peripheral calcified lesion was also identified. Very severe marginal calcification was detected in the inferior portion of the nodule, which was barely observable in ultrasonography (). Unilateral fixed vocal cords were revealed in a paramedian position. Vocal cord paralysis was suspected on the right side ().\nA total thyroidectomy was performed. A 4.5-cm solid mass of the right thyroid lobe was closely adhered to the surrounding airway and recurrent laryngeal nerve. It was impossible to completely dissect the mass from the nerve.\nThe resected mass was covered by a thin capsule, and its cut surface showed mixed strips of white, yellowish-brown, and pink colors. Peripheral dense calcification was also seen. Microscopic examination revealed that thyroid follicles were replaced by extensive inflammatory and fibrous tissue. Inflammation was also noticed in the vein, which was encased in fibrous tissue, but no malignant cells were found. Based on these pathologic characteristics, RT was diagnosed ().\nThe patient recovered from RT, and there were no signs of complications. She is currently taking 100 µg levothyroxine while undergoing postsurgical outpatient follow-up. She has not yet recovered from her vocal cord paralysis.