Primary squamous cell carcinoma of the thyroid: a case report.

: Primary squamous cell carcinoma of the thyroid is a very rare thyroid malignancy (less than 1% of thyroid cancers) with unfavorable clinical evolution and median survival less than one year, due to highly local tumor invasiveness with airway obstruction, metastases and treatment complications. We present a 62-year-old female patient with a fixed, rapidly increasing 5 cm right thyroid nodule, generating compressive signs and significant weight loss, resembling anaplastic thyroid carcinoma. Thyroid hormones, antithyroid antibodies and calcitonin were normal. Computed tomography (CT) scan revealed mediastinal extension of the tumor and excluded the presence of lymph nodes or other tumors (T3N0M0). Total thyroidectomy was performed and histopathological evaluation revealed squamous cell carcinoma, which was confirmed by immunohistochemistry, showing diffuse positivity for CK7, CK19, CK34βE12, galectin-3, EGFR, focal positivity for p63 and negativity for TTF-1 and CD5. Subsequently, the patient underwent chemotherapy (Paclitaxel, Cisplatin, Epirubicin) and radiotherapy (40 Gy), but tumor recurrence was noticed one month after surgical resection and continued to grow despite treatment. Nodal and metastases status remained negative at regular follow-up. The patient died within one year after diagnosis. External radiotherapy and chemotherapy were not efficient in our case. New treatment options are needed to improve outcome in primary squamous cell carcinoma of the thyroid.