Presence of the BRAF V600E point mutation in morphologically benign appearing thyroid inclusions of cervical lymph nodes.

The biologic nature of morphologically bland-appearing thyroid inclusions in cervical lymph nodes continues to be a controversial topic. The diagnosis of benignity entails a much more conservative clinical approach than does malignancy. Arriving at the correct interpretation, however, can be difficult when only morphologic examination is performed. Incorporating the use of the recently identified BRAF V600E point mutation, a highly specific biomarker for papillary carcinoma of the thyroid, may provide a useful adjunct in assessing the biologic nature of morphologically bland-appearing thyroid inclusions in cervical lymph nodes. In this case report, bland thyroid inclusions were noted in addition to a primary papillary carcinoma of the thyroid and morphologically recognizable cervical lymph node metastasis. Cells from these separate entities were procured by lasercapture microdissection, and the DNA was isolated, amplified, and sequenced. Molecular analysis provided integral data indicating these morphologically bland thyroid inclusions were malignant, findings not readily apparent by morphologic examination alone.