Table 2.

Review of Utilization of Ancillary Studies in Thyroid FNA

Suspected medullary carcinoma

• IHC panel (calcitonin, thyroglobulin, CEA, chromogranin)

• Serum calcitonin

Suspected anaplastic carcinoma

• IHC for pan-cytokeratin

Suspected metastatic carcinoma

• IHC for TTF-1 (If TTF-1 negative, then expand IHC panel based on cytomorphology and clinical setting to identify primary)

Suspected lymphoma

• Flow cytometric immunophenotyping

Suspected parathyroid lesion

• IHC for TTF-1, PTH, chromogranin

• May consider PTH level assessment on FNA sample

Suspected metastatic thyroid carcinoma to lymph node

• IHC for TTF-1, thyroglobulin, calcitonin

• May consider thyroglobulin level assessment on FNA sample

Atypical/Borderline/Suspicious FNA

• No specific tests based on insufficient evidence