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Employing Digital Droplet PCR to Detect BRAF V600E Mutations in Formalin-fixed Paraffin-embedded Reference Standard Cell Lines
Published on: October 8, 2015
False-positive FNA due to highly sensitive BRAF assay
Monica M DiLorenzo1, Jeffrey L Miller2, Madalina Tuluc3
1Department of Otolaryngology, Head, and Neck Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania.
Summary
Highly sensitive BRAF testing can lead to false-positive results in indeterminate thyroid fine-needle aspirations (FNA). This case highlights the importance of considering assay limitations and the positive predictive value of BRAF mutation detection.
Area of Science:
- Endocrinology
- Oncology
- Molecular Diagnostics
Background:
- False-positive BRAF V600E mutation results in thyroid fine-needle aspiration (FNA) are uncommon but may increase with sensitive assays.
- Assays detecting BRAF V600E in 2% of wild-type cells pose a risk for false positives in indeterminate FNA cases.
Purpose of the Study:
- To report a case of an indeterminate BRAF-positive FNA with a false-positive BRAF V600E mutation result.
- To discuss the implications of highly sensitive BRAF assays on diagnostic accuracy in thyroid nodules.
Main Methods:
- Case report of an 87-year-old female with a thyroid nodule.
- Fine-needle aspiration (FNA) with BRAF molecular analysis.
- Thyroid lobectomy and subsequent surgical pathology review.
- Literature review on BRAF testing in thyroid FNA.
Main Results:
- The patient's FNA was reported as BRAF-positive, leading to an indeterminate diagnosis.
- Surgical pathology revealed a benign adenomatoid nodule.
- Microdissection and molecular testing of the benign nodule showed wild-type BRAF at the assay's limit.
Conclusions:
- Highly sensitive BRAF assays can detect mutations in as few as 2% of cells, increasing the risk of false-positive results in indeterminate thyroid FNAs.
- Clinicians should be aware that BRAF molecular testing may not have a 100% positive predictive value.
- Caution is advised when interpreting BRAF results in the context of indeterminate FNA findings.
