Differentiated Thyroid Cancer: Clinical and Pathologic Characteristics (5)
| Histological subtypes | Morphology | Molecular markers | Pattern of spread | RAI avidity |
|---|---|---|---|---|
| Papillary thyroid cancer (PTC) | Classical papillae Clear nuclei | BRAF V600E, RET/PTC fus | Lymph nodes | ++++ |
| PTC–follicular variant | Follicular structures Clear nuclei | BRAF K601E, RAS, PAX8/PPARγ | Lymph nodes | +++++ |
| PTC–aggressive variants* | Specific cell features and structural changes | BRAF V600E, 1q amp, TERT promoter | Lymph nodes Lung | +++ |
| Follicular thyroid cancer | Capsular invasion (MI) Vascular invasion (WI) Extrathyroidal invasion (WI) | RAS, PAX8/PPARγ, PTEN, TSHR, TERT promoter | Lung Bone | +++++ |
| Hürthle cell thyroid carcinoma | Hürthle cells | RAS, PAX8/PPARγ, PTEN, TSHR, chromosomal loss, mitochondrial DNA mutations, TERT promoter | Lung Bone | ++ |
| Poorly differentiated thyroid cancer | Invasion Mitoses >3 Necrosis Convoluted nuclei | RAS, TERT promoter, TP53, PIK3CA, PTEN, CTNNB1, AKT1, EIF1AX, ALK fus | Lymph nodes Lung Bone | +/– |
| Anaplastic thyroid cancer | Undifferentiated cells with immunohistochemical or ultrastructural features of epithelial origin but of morphological and immunophenotypic markers of thyroid origin | TP53, TERT promoter, PI3K/AKT/mTOR, SWI/SNF subunts, RAS, EIF1AX, BRAF | Local invasion Lung Bone Lymph nodes | – |
* Tall, columnar, solid, and hobnail variants.
RAI = radioiodine; MI = minimally invasive; WI = widely invasive; fus = fusion.