Mixed squamous cell carcinoma and follicular carcinoma of the thyroid gland

Primary squamous cell carcinoma of the thyroid gland (PSCCT) is rare and its aetiology is debated. A 67-year-old man presented with neck mass. Fine-needle-aspiration (FNA) cytology and through-cut biopsy were suggestive of poorly differentiated or anaplastic carcinoma. The patient was offered tracheostomy and palliative cure for unresectable tumor of the thyroid; he refused and decided for other opinion. Lobe-isthmusectomy was performed with diagnostic and debulking intent. Final pathology report was of mixed squamous cell and follicular carcinoma of the thyroid. The tumor was a PSCCT. The patient underwent adjuvant chemoradiotherapy. After 2 years, an iliac crest metastasis of follicular carcinoma was diagnosed. The patient is disease free, after surgery and radio-active-iodine treatment. The hypothesis of squamous cell carcinoma transformation from well differentiated thyroid cancer has to be considered in case of PSCCT. Primary squamous cell carcinoma of the thyroid gland (PSCCT) is rare [1-3]; different theories on its aetiology do exist [4-6]. Mixed squamous cell and follicular carcinoma is even more rare than pure squamous cell of the thyroid gland and only few cases are reported in literature [7]. Preoperative diagnosis can be very challenging and the differential diagnosis with secondary squamous cell carcinoma of the thyroid (SSCCT) is manadatory in order to plan a correct management of the disease. The presence of PSCCT with distant metastasis of follicular carcinoma supports the histogenesis of squamous cell carcinomas arising from follicular epithelial cells.