ABSTRACT
Objective:To investigate the clinicopathological features and prognosis of medullary thyroid carcinoma (MTC) co-existent with Hashimoto's thyroiditis (HT).Methods:Seven cases of MTC co-existent with HT were collected from Fujian Cancer Hospital between Jan 2007 and May 2021. Its clinicopathological features were analyzed.Results:All patients were adult female with a median age of 49 years, and 6 of them were unilateral MTC. The tumor diameter ranged from 0.4 to 7.0 cm. The thyroid tissue surrounding the tumor showed HT. The follow-up time was 16 to 152 months, with a median time of 61 months, 5 patients (tumor diameter <1 cm) were biochemically cured, 1 patient (tumor diameter >1 cm) was anatomically cured. The another patient died due to tumor progression 30 months after surgery, the tumor cells in which were highly atypia and more mitoses (5~8/10HPF) necrosis and vascular invasion were also observed.Conclusion:MTC with HT are mostly sporadic cases, and most of them have a fair prognosis.