Hürthle Cell Carcinoma of the Thyroid Gland: Systematic Review and Meta-analysis

Introduction: Hürthle cell carcinoma (HCC) comprises about 5% of thyroid carcinoma cases. Partly because of its rarity there is much we still need to know about HCC as compared to other histological cancer subtypes. Methods: We conducted a systematic literature review following PRISMA guidelines and meta-analysis, from 2000 to 2020, to investigate the main characteristics of HCC and clarify information concerning tumor behavior and treatment. Results: Our review included data from 9638 patients reported in 27 articles over the past 20 years. This tumor occurred more frequently in women (67.5%). The mean age was 57.6 years, and the mean size of the neoplasm at diagnosis was 30 mm. Extrathyroidal extension was common (24%) but lymph node metastasis was not (9%). Total thyroidectomy was the most common surgical approach, with neck dissection usually performed in cases with clinically apparent positive neck nodes. Radioiodine therapy was frequently applied (54%), although there is no consensus about its benefits. The mean 5- and 10-year overall survival was 91% and 76%, respectively. Conclusion: This review serves to further elucidate the main characteristics of this malignancy. HCC of the thyroid is rare and most often presents with a relatively large nodule, whereas lymph node metastases are rare. Given the rarity of HCC, a consensus on their treatment is needed, as doubts remain concerning the role of specific tumor findings and their influence on management.