Thyroid Metastasis of Squamous Cell Carcinoma in an Unsuspected Patient

Abstract

Malignancies metastasizing to thyroid are a very rare phenomenon. Out of them all, diagnosis of metastatic squamous cell carcinoma in thyroid can be difficult to establish as in thyroid there can also be a primary thyroid squamous cell carcinoma SCC.We herein report a rare case of a 28-year old man with metastasis of oral SCC the thyroid gland. He was operated six months back, took incomplete cycles of adjuvant chemo-radiotherapy. On FDG-PET CT was found to have metabolically active lesions in right lobe of thyroid along with right paratracheal and bilateral cervical nodes.Fine needle aspiration cytology (FNAC) smears from thyroid showed malignant squamous cells. Considering various factors like previous history, histopathology, present FDG-PET scan findings and present cytology diagnosis was concluded to be metastatic over primary thyroid SCC.It is necessary to differentiate between primary or metastatic SCC in thyroid as they are different in clinical and prognostic behaviour. Primary squamous cell carcinoma is very aggressive with a poor prognosis.