Thyroid cancer

Thyroidectomy is a treatment option for thyroid cancers and hyperthyroidism.
Potential complications of the surgery include hoarseness (due to damage to the recurrent laryngeal nerve), hypocalcemia (due to removal of the parathyroid glands), and transection of the recurrent and superior laryngeal nerves (during ligation of the inferior thyroid artery and superior laryngeal artery, respectively).

Types of Thyroid Cancer.

The two most common malignancies originating from the thyroid follicular epithelium are papillary thyroid cancer (PTC, which is the most common type) and follicular thyroid cancer (FTC).
Microscopically, PTC consists of branching papillae with a fibrovascular stalk lined by a single or multiple layers of cuboidal epithelium. The nuclei of these epithelial cells have a characteristic ground-glass appearance.
Concentrically calcified structures, known as psammoma bodies, are usually present and are also characteristic. Psammoma bodies are not seen in any other thyroid malignancy apart from PTC.
The prognosis for patients with papillary thyroid cancer is generally good.
Psammoma bodies and ground glass, grooved nuclei, Empty-appearing nuclei with central clearing (“Orphan Annie” eyes) are characteristic microscopic features of papillary cancer of the thyroid gland.
Lymphatic invasion common.
↑ risk with RET and BRAF mutations, childhood irradiation.

Follicular thyroid cancer (FTC) is the second most common type of thyroid cancer. Histologically, FTC can be well-differentiated, resembling normal thyroid morphology, or less well-differentiated, consisting of sheets of follicular cells or large cells with eosinophilic cytoplasm.
FTC and papillary thyroid cancer (PTC) are differentiated based on the presence of ground glass nuclei and psammoma bodies in PTC.
The distinguishing feature of FTC from benign follicular adenomas is its capsular and vascular invasion. Overall, the prognosis is good.

Medullary thyroid cancers are tumors that originate from parafollicular calcitonin-secreting C-cells. Approximately 80% of these cancers are sporadic, while 20% are familial, as seen in the MEN type 2 syndrome.
Germline mutations of the RET proto-oncogene are present in over 95% of patients with familial medullary thyroid cancer. These mutations are also commonly found in sporadic cases. Activating mutations of the RET proto-oncogene are strongly linked with medullary thyroid cancer and are associated with MEN 2A and 2B syndromes.
Microscopically, these cancers consist of uniform polygonal or spindle-shaped cells with extracellular amyloid deposits, which are derived from secreted calcitonin. These amyloid deposits stain with Congo red. Medullary thyroid cancer often spreads through blood vessels.

Anaplastic thyroid carcinoma is a highly aggressive tumor with a poor prognosis. Its one to two-year mortality rate approaches 100% due to the tumor's tendency to invade nearby structures and metastasize to distant sites.
Microscopically, this tumor comprises large pleomorphic cells and large multinucleated osteoclast-like cells. Occasionally, small cells mixed with spindle cells are also observed. The psammoma bodies and ground glass nuclei, typically seen with Papillary Thyroid Cancer (PTC), are not present in anaplastic cancer.