Classification
It is impossible to distinguish between follicular adenoma and carcinoma on cytological grounds. If fine needle aspiration cytology (FNAC) suggests follicular neoplasm, thyroid lobectomy should be performed to establish the histopathological diagnosis. Features sine qua non for the diagnosis of follicular carcinoma are capsular invasion and vascular invasion by tumor cells. Still, focuses of the capsular invasion should be carefully evaluated and discriminated from the capsular rupture due to FNA penetration resulting in WHAFFT (worrisome histologic alterations following FNA of thyroid).
- Follicular carcinoma tends to metastasize to lung and bone via the bloodstream.
- Papillary thyroid carcinoma commonly metastasizes to cervical lymph nodes.
HMGA2 has been proposed as a marker to identify malignant tumors.
Read more about this topic: Follicular Thyroid Cancer