Abstract
BACKGROUND: Hereditary medullary thyroid carcinoma (MTC) is mainly caused by germline mutations in the RET proto-oncogene, which accounts for 20-30% of all MTC according to foreign studies. However, no English literatures have reported Chinese hereditary MTC. Here, we reported two Chinese brothers with MTC that caused by germline RET mutation. CASE PRESENTATION: The younger brother was diagnosed with MTC at 29 years ago and suffered recurrence more than 10 years. For elder brother, the diagnosis of MTC was made by postoperative pathological examination at age 61. Both patients received total thyroidectomy and lymph node dissection. Since they had a significant family history for MTC, genetic detection was performed and identified a germline mutation in RET exon 10 (p.C620Y). This mutation was also detected in their offspring, indicating a moderate risk of MTC. CONCLUSIONS: This is the first report presenting a Chinese family with hereditary MTC caused by the RET p.C620Y variant. This case series emphasize the importance of genetic detection of RET proto-oncogene for MTC patients, and bring out managements for individuals after detection of RET mutations.