Primary Squamous Cell Carcinoma of the Thyroid: A Case Report and Literature Review About a Rare Entity.

Primary squamous cell carcinoma of the thyroid (PSCCT) is a rare and aggressive neoplasm that accounts for less than 1% of all thyroid malignancies. Its incidence is higher in females in their fifth and sixth decades of life. The pathophysiology of PSCCT is still a subject of debate as squamous cells are generally absent in the thyroid gland under normal physiologic conditions. Immunohistochemistry is important for reaching a definite diagnosis as it helps to differentiate PSCCT from metastases from other primary sites. Clinically, PSCCT usually presents as a rapidly enlarging anterior neck mass. Surgical resection is the mainstay of treatment despite the lack of any standard guidelines for the same given the rarity of the disease. Adjuvant chemotherapy, radiotherapy, and targeted therapy continue to be of unclear benefit. We report a case of PSSCT in a male patient who presented with a rapidly enlarging neck mass.