Cytopathology of the distant metastasis of papillary carcinoma of thyroid

To describe the cytomorphological features at distant metastatic sites apart from lymph nodes in papillary thyroid carcinoma (PTC).A total of eight cytology cases from seven patients reported as metastatic papillary carcinoma of thyroid were reviewed including available clinical and radiological details. The details clinical and cytological features were studied.There were a total of five males and two female patients. Two of these patients presented with lung nodules, two patients had bony lesion and lesion in kidney respectively and one patient had both bony and soft tissue lesions. Pleural fluid and bronchoalveolar lavage were received from remaining two patients. Cytology smears revealed papillary clusters and sheets of tumor cells, having round to oval nuclei with pale powdery chromatin, inconspicuous nucleoli and scant to moderate amount of cytoplasm. Nuclear features such as longitudinal nuclear grooves, intranuclear cytoplasmic inclusions were seen in all but one case. Nuclear enlargement and overlapping were variably present.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.