Not all neck mass fine-needle aspirations with squamous cells are squamous cell carcinoma; report of a case of recurrent thyroid carcinoma with papillary and squamous components

We report a case of a 65-year-old female who had a total thyroidectomy 12 years ago for papillary thyroid carcinoma (PTC) who presented with a recurrent thyroid bed mass. Fine-needle aspiration biopsy yielded malignant cells, consistent with squamous cell carcinoma (SCCa). Surgical resection was performed, and histologic evaluation of the mass showed mixed PTC and SCCa. The tumor cells were positive for BRAF V600E mutation. Thyroid carcinomas with admixed papillary carcinoma and SCCa are rare and are associated with aggressive behavior, high rates of metastasis, and poor outcomes. Although SCCa presenting as a neck mass is relatively common, clinical history and appropriate workup are essential for accurate diagnosis and determination of origin.