<unk>  epithelial<unk> s are not found in normal thyroid, thus the origin of SCTC is not clear. However, it might be a derived from the embryonic remnants such as thyroglossal duct or branchial clefts. Often SCTC is diagnosed in one of the thyroid lobes, but not in the pyramidal lobe. Another possible way of SCTC development can be through the<unk>  metaplasia of<unk> s. However, that theory is also controversial, since the Hashimoto's thyroiditis and chronic lymphocytic thyroiditis (neoplasms to be showed<unk>  metaplasia) are not associated with SCTC. Primary STCT is usually diagnosed in both lobes of thyroid gland. The histopathology of STCT shows a<unk>  differentiation of tumor<unk> s.
Squamous-cell thyroid carcinoma
Thyroid lymphoma
Anaplastic thyroid cancer
Papillary thyroid cancer
Medullary thyroid cancer
Follicular thyroid cancer
Poorly differentiated thyroid cancer
Thyroid adenoma