Abstract
RATIONALE: Papillary thyroid carcinoma (PTC), the predominant subtypes accounting for approximately 85% of thyroid carcinomas, has a rapidly increasing global incidence rate. Statistically, approximately 74.6% PTC patients had the genomic variants of BRAF, especially BRAFV600E mutation, which has been reported to stratify patients and guide clinic-therapies. However, some PTC patients may carry other nonclassical mutation patterns of BRAF, due to the complex of genomic instability. And the spectrum of BRAF mutation was not fully characterized. We reported a novel BRAF mutation pattern of PTC. PATIENT CONCERNS: A 59-year-old woman was admitted to our hospital because of the slight enlargement of bilateral cervical lymph nodes in July 2023. DIAGNOSIS: Ultrasonography revealed that the bilateral thyroid nodules of the patients both presented 1 hypoechoic nodule, which was graded as 3 of the elastic score, and the small calcification in the right lobe (Chinese-Thyroid Imaging Reporting and Data System 4c). Pathological diagnosis showed the interstitial collagen change and focal follicular epithelial papillary hyperplasia with atypical hyperplasia of the bilateral thyroid. Further puncture pathology showed that the patient had a malignant thyroid lesion with the phenotypes of papillary carcinoma and diagnosed with malignancy subsequently. Additionally, the patient harbored a novel insert on BRAF exon 15, a 6-base fragment AGACAG inserting between c.1798 and c.1799. INTERVENTIONS: The patient was undergone on microwave ablation of thyroid carcinoma on July 28, 2023. After the surgery, the patient was treated on anti-infection, cold saline external application of bilateral thyroid swelling supportive treatment. OUTCOMES: No postoperative complications or recurrence and metastasis were found. LESSONS: This is the first case of the novel nonclassical genomic variant of BRAF. Our study extends the spectrum of BRAF mutations. The patient had a favorable response to microwave ablation, indicating that in spite of the association between this mutation and high-grade malignant phenotype, this genomic variant of BRAF did not have a detrimental effect on the response of clinical treatment.