Squamous-cell carcinoma of the thyroid

Pathophysiology

Squamous epithelial cells are not found in a normal thyroid, so the origin of Squamous-cell carcinoma of the thyroid is not clear. However, it might be derived from embryonic remnants such as thyroglossal ducts or branchial clefts. It is oftendiagnosed in one of the thyroid lobes but not in the pyramidal lobe. Another way it may develop is through the squamous metaplasia of cells. However, that theory is also controversial since Hashimoto's thyroiditis and chronic lymphocytic thyroiditis (neoplasms to be shown squamous metaplasia) are not associated with squamous-cell carcinoma of the thyroid. Primary squamous-cell carcinoma of the thyroid is usually diagnosed in both lobes of the thyroid gland. The histopathology shows a squamous differentiation of tumor cells.

Diagnosis

Squamous-cell carcinoma of the thyroid is biologically aggressive malignant neoplasm which is associated with rapid growth of neck mass followed by infiltration of thyroid-adjacent structures. Patients usually demonstrate dysphagia, dyspnea and voice changes, as well as local pain in the neck.

The tools required to diagnosis primary squamous cell carcinoma of the thyroid are panendoscopy, CT-Scan or PET-CT and immunohistological analysis.

Treatment

Thyroidectomy and neck dissection show good results in early stages of squamous-cell carcinoma of the thyroid. However, due to highly aggressive phenotype, surgical treatment is not always possible. It refractive to radioiodine treatment. Radiotherapy might be effective in certain cases, resulting in relatively better survival rate and quality of life. Vincristine, doxorubicin and bleomycin are used for adjuvant chemotherapy, but their effects are not good enough according to publications.

Prognosis

Squamous-cell carcinoma of the thyroid exhibits a highly aggressive phenotype, thus prognosis of that malignancy is extremely poor. The overall survival is less than 1 year in most of cases.

References

References

1. MI Syed. (2011). "Squamous cell carcinoma of the thyroid gland: primary or secondary disease?". The Journal of Laryngology & Otology.
2. "Squamous Cell Carcinoma".
3. (2017). "Primary squamous cell carcinoma of the thyroid: Case report and systematic review of the literature". Int J Surg Case Rep..
4. Dimov, Rossen S.. (November 2013). "The effect of neck dissection on quality of life in patients with differentiated thyroid cancer". Gland Surgery.
5. (2006). "Primary squamous cell carcinoma of the thyroid: report of ten cases". Thyroid.