Cytopathology of the distant metastasis of papillary carcinoma of thyroid.

The diagnosis of metastatic PTC at uncommon locations is difficult. Since many of these locations are amenable to fine needle aspiration or exfoliative cytology evaluation, clinical awareness, and identification of classic cytomorphologic features can offer quick and accurate diagnoses. In cases with occult or unknown PTC presenting with metastases, cytomorphology may help in the prompt suggestion of detecting primary tumor in the thyroid.