Epidemiology and prognostic factors of Hürthle-oncocytic cell carcinoma of the thyroid

INTRODUCTION: Hürthle cell carcinoma (HCC) -recently known as oncocytic carcinoma- is a rare type of differentiated thyroid cancer that presents a diagnostic and therapeutic challenge because of its morphological heterogeneity and uncertain biological behavior. METHODS: This retrospective single-center cohort study included all the patients with HCC who underwent surgical treatment in our center from January 2009 to May 2024. The epidemiological, clinical, and oncological data of the included patients were analyzed. RESULTS: This study included nineteen cases of HCC (9 males and 10 females). The average age at diagnosis was 54.8 ± 12.2 years. Preoperative fine needle aspiration cytology (FNAC) classified 2 tumors as Bethesda I, 7 as Bethesda III, 6 as Bethesda IV, and 4 as Bethesda V. A variety of surgical procedures were used, including hemithyroidectomy in 3 patients and total thyroidectomy in 12 patients. Two patients underwent neck dissection. The median tumor size was 6.7 cm. Pathological evaluation identified 9 patients with unifocal lesions and 10 with multifocal lesions. Only one patient showed positive lymph node involvement. The median times to death, distant metastasis, and locoregional recurrence were 4, 13, and 6 years, respectively. For locoregional recurrence, the restricted mean survival time (RMST) at five years was 4.4 years (95% CI 3.9-4.9), 4.6 years (95% CI 4.1-5.0) for distant metastasis, and 4.1 years (95% CI 3.6-4.5) for overall survival. There was a trend towards worse prognosis in females, younger age, and those with primary surgery outside the center. These differences did not achieve statistical significance, at least partly due to the small sample size. CONCLUSION: Diagnosing HCC remains challenging due to its overlapping features with other thyroid conditions, making fine-needle aspiration cytology less definitive. Surgical treatment remains the preferred therapeutic option. Age, gender, and the volume of the surgical center for the initial procedure can influence patient outcomes, particularly recurrence and survival rates.