Case of concurrent Riedel's thyroiditis, acute suppurative thyroiditis, and micropapillary carcinoma
A 48-year-old woman visited our hospital due to abdominal pain and fever of 3 days' duration. She received antibiotic treatment under the diagnosis of cholecystitis with gallstones and liver cirrhosis. The patient began to experience pain and swelling in the anterior neck region at the time of hospitalization. As her symptoms became aggravated, she was referred to the endocrinology department. The patient's history revealed the consumption of a bottle of alcohol five times a week over the previous 20 years. The remainder of her medical history was unremarkable.\nAt the time of consultation, the patient's blood pressure was 130/60 mmHg, her heart rate was 68 beats/min, and her body temperature was 37.6℃. She was alert but had an acute ill-looking appearance. Jaundice was observed in the sclera and a 3 × 3 cm hard mass fixed around the right anterior area of the neck, accompanied by tenderness and enlargement of adjacent cervical lymph nodes, was palpated. The patient complained of abdominal pain and had direct tenderness in the right upper quadrant of her abdomen. There was no palpable organ or mass in the abdomen.\nLaboratory examinations showed a hemoglobin count of 10.7 g/dL, a leukocyte count of 11,100/mm3 (neutrophils 76.0%, lymphocytes 17.0%, monocytes 3.4%, and eosinophils 1.1%), a thrombocyte count of 101,000/mm3, an aspartate aminotransferase level of 84 IU/L, an alkaline aminotransferase level of 40 IU/L, an alkaline phosphatase level of 311 IU/L, a total protein and albumin level of 6.7/2.3 g/dL, a total bilirubin level of 6.5 mg/dL, a glucose level of 114 mg/dL, a γ-GT level of 141 IU/L, a prothrombin time of 20.9 seconds (46%), an erythrocyte sedimentation rate of 120 mm/hr, and a C-reactive protein level of 4.42 mg/dL. Moreover, the serum thyroid stimulating hormone level was 1.23 mIU/L (normal range, 0.17 to 4.05), the T3 level 36.0 ng/dL (normal range, 60.0 to 190.0), the free T4 level 1.09 ng/dL (normal range, 0.80 to 1.90), the thyroglobulin antibody (Ab) level 113.71 U/mL (normal range, 0.00 to 100.00), and the microsomal Ab level 4.0 U/mL (normal range, 0.0 to 70.0). Blood culture carried out at the time of hospitalization showed growth of Escherichia coli and urine culture showed growth of Enterococcus species, which led to treatment with piperacillin/tazobactam and amikacin.\nThe chest X-ray was normal. Cervical computed tomography revealed a large nodular lesion of the right thyroid lobe with internal calcification and an irregular border, suggesting a malignant nodule. There was swelling and liquid collection in the surrounding soft tissue, which seemed to be due to accompanying hemorrhage or inflammation. Cervical lymphadenopathy of the level II lymph nodes on both sides and the level III and IV lymph nodes on the right side was observed (). Positron emission tomography revealed strong fluorodeoxyglucose (FDG) uptake by a large nodule of the right thyroid lobe and cervical lymphadenopathy at the left level IB lymph nodes, the level II lymph nodes on both sides, and the right level III, IV, and V areas, with strong FDG uptake. The results suggested malignancy of the right thyroid gland and abnormal cervical lymphadenopathy. On the basis of these findings, neck ultrasonography and ultrasound-guided fine needle aspiration biopsy (FNAB) were carried out. A 3.06 × 2.63 × 3.91 cm heterogeneous hypoechoic mass with calcification was observed in the right lobe of the thyroid gland, and FNAB was performed (). Aspiration of the nodule collected 10 mL of puslike fluid. Aspiration cytology results revealed no thyroid follicles, but fibrous tissues and spindle cells with numerous neutrophils, lymphocytes, and macrophages were observed (). Culture of the aspirated fluid resulted in the growth of E. coli.\nAfter antibiotic therapy for acute suppurative thyroiditis, follow-up ultrasound-guided FNAB for the thyroid nodule was carried at 2 months. Ultrasonographic findings revealed a 3.4 × 3.6 × 3.5 cm hypoechoic nodule accompanied by calcification in the right thyroid lobe, suggesting a malignant nodule. Metastasis to the cervical lymph nodes was also suspected since the level II lymph nodes of the right cervical region were enlarged to 1.2 cm and hyperechoic findings suggested internal calcification. Cytologic analysis of the right thyroid nodule showed no evidence of malignancy. No follicle cells were seen; only a mixture of various inflammatory cells was observed. Ultrasound-guided FNAB was repeated a total of five times as the possibility of malignancy could not be ruled out. There was a single report of suspicion of malignancy and the other four biopsies resulted in a benign diagnosis or insufficient specimens. Surgical biopsy was recommended since anaplastic carcinoma accompanied by inflammation could not be ruled out. Surgical biopsy was performed for accurate histological diagnosis and treatment.\nAnalysis of a frozen biopsy section revealed a benign inflammatory disorder. However, since the possibility of malignancy could not be ruled out, total thyroidectomy and excision of the central cervical lymph nodes was performed. During the operation, a large hard nodule with adhesion to neighboring structures, including adjacent muscles and the internal jugular vein, was found in the right thyroid lobe. On gross examination, the cut surface revealed a hard grayish brown nodule with fibrosis, accompanied by multifocal necrosis and calcification. Histologic examination revealed loss or contraction of normal thyroid follicles of the right thyroid gland due to severe fibrosis, and many areas affected by localized abscesses, cholesterol crystallization, degenerative calcification, and infiltration of acute and chronic inflammatory cells (). In addition, the characteristic findings of chronic inflammation and fibrous tissues encasing a medium-sized vein were observed (, inset). Fibrous tissues and inflammation infiltrated the skeletal muscles around the thyroid gland (). In the left thyroid gland, a 0.15 cm micropapillary carcinoma was observed. On the basis of these findings, RT accompanied by acute suppurative thyroiditis and micropapillary carcinoma was diagnosed. The patient is currently being treated on an outpatient basis with thyroid hormone replacement therapy (150 µg of levothyroxine per day).