Clinical debate on papillary thyroid microcarcinoma-could genetic testing change the decision of papillarythyroid microcarcinoma (mPTC) treatment: A case report

Abstract

The objective of this case report is to explore whether genetic testing is appropriate to guide the treatment of papillary thyroid microcarcinoma (PTMC). In this case report, we describe a 27-year-old female who had no significant medical history and no tumor detected in the thyroid gland by ultrasound or computed tomography (CT), but had multiple enlarged lymph nodes at the right cervical lymph node levels II, III, IV, and V. The intraoperative frozen section pathology results showed that seven out of 23 right lymph nodes were metastatic from thyroid papillary carcinoma, but no primary lesion was found in the thyroid gland. After multiple post-operative sampling and micro section, only a 1 mm papillary carcinoma in the left thyroid gland was identified. The genetic testing result showed that the patient was positive for CCDC6-exon 1-RET-exon 12 fusion. The final diagnosis of the patient was left thyroid micro-papillary carcinoma (1 mm) with the right lateral cervical lymph node metastasis. She received iodine-131 treatment with nuclide and lifelong levothyroxine therapy in the 3rd month after surgery. Continuous follow-up showed no elevation of thyroglobulin, no recurrence signs on positron emission tomography-CT re-examination, and good self-reported health status. In conclusion, the identification of CCDC6-RET fusion by genetic testing in the PTMC case aided diagnosis and treatment.