Curriculum · Metabolic and Endocrine and Diabetes Mellitus
Thyroid cancer subtypes
What it is
The most common histological subtypes of thyroid cancer are papillary followed by follicular thyroid cancer; these two are the differentiated cancers. Hurthle cell sits beside follicular. Medullary thyroid cancer originates from the parafollicular cells, the C cells. Anaplastic thyroid cancer is usually associated with other differentiated thyroid cancers and it generally has a poor prognosis. Two more sit outside that line: primary thyroid lymphoma, which is treated with chemotherapy and/or radiation, with the role of surgery limited to obtaining tissue biopsy; and metastases to the thyroid gland from extrathyroidal primary cancers, which are rare and come most commonly from renal cell carcinoma in clinical series and the lung in autopsy series.
Papillary
Patients with papillary thyroid cancer usually have Psammoma bodies, Papillary projections and Orphan Annie cells with ground glass nuclei, which is remembered as the 3 Ps. Its distinctive feature is that it is multifocal and nodal. Radioactive iodine (RAI) is selective, for intermediate and high risk. TSH suppression goes by risk: high risk < 0.1, intermediate 0.1-0.5, low 0.5-2.0. The adjuvant and systemic line is RAI plus a TKI (lenvatinib or sorafenib) if RAI-refractory. Follow up with Tg q6-12 mo plus US neck. Prognostic factors are age < 55 better, ETE, LN and size, and 10-yr survival is > 95 %. One local note: papillary CA in gulf countries tends to be aggressive compared to other areas.