Diagnosis and management of 34 Hürthle cell tumors.

Background: Controversies still exist around the diagnosis and management of Hürthle cell tumors. The aim of this study is to reexamine our experience to improve our methods in the future.

Methods: We treated 34 patients with verified Hürthle cell carcinoma and adenoma at Chang Gung Memorial Hospital, Linkou from 1990 through 1996. Clinical characteristics, thyroid ultrasonogram, 131I, 201Tl, 99mTc-methoxy-isobutyl-isonitrile (MIBI) and 99mTc-thyroid scan, fine needle aspiration cytology (FNAC) and histology results were analyzed.

Results: Female predominance (82.4%) was noticed among our Hürthle cell tumors. Nine (26.5%) patients had carcinoma. The median size of carcinoma was 4.0 cm, which was significantly larger than the median 3.0 cm for adenoma. No significant differences were found between gender, age, multiplicity or echogenicity between two groups. All 12 adenoma and 3 carcinoma patients who received pre-operative 99mTc and/or 131I thyroid scan showed cold nodules. The sensitivity and specificity of detection Hürthle cell carcinoma as indeterminate and malignant using FNAC was 78% and 18% respectively. These improved to 100% and 86% using frozen sections. One carcinoma patient developed neck lymph node metastasis, with normal serum thyroglobulin, negative 131I but positive 201Tl and 99mTc-MIBI whole body scans. Another one showed mediastinum metastasis with elevated serum thyroglobulin, detected using 131I scan, revealed successful regression after 131I therapeutic scan.

Conclusion: Tumor size of carcinoma is significantly larger than adenoma. All patients with FNAC suggestive of Hürthle cell tumors should receive surgery for histological diagnosis to differentiate carcinoma from adenoma. Therapeutic radioiodine ablation is indicated whenever there is 131I uptake by tumor cells.