Liver metastasis of thyroid papillary carcinoma diagnosed by aspiration cytology A case report

Background: Liver metastasis of thyroid papillary carcinoma is exceedingly rare. Case: An 87-year-old man admitted for leg edema was found in imaging to have a liver tumor clinically diagnosed as cystadenocarcinoma. Intraoperative fine-needle aspiration cytology (FNAC) was done. Aspirates consisted of numerous papillary clusters and sheets of epithelial tumor cells and scattered macrophages. Colloid-like materials and psammoma bodies were also found on smears. Tumor cells had irregular nuclei with fine pale chromatin and showed nuclear grooves, intranuclear cytoplasmic inclusions, and intracytoplasmic septate vacuoles. Squamous metaplastic cells and multinucleated giant cells were also observed. These cytologic features were reminiscent of thyroidpapillary carcinoma. Histologically, the resected tumor resembled thyroid papillary carcinoma with marked degenerative changes. Immunohistochemically, tumor cells were positive for thyroglobulin and thyroid transcription factor 1. These results suggest that the liver tumor was thyroid papillary carcinoma in origin. Conclusion: Because thyroid papillary carcinoma was suspected by intraoperative FNAC and on subsequent inquiry, a history showed that the patient had undergone an operation for thyroid papillary carcinoma (pT2N1, stage III) 19 years ago. FNAC proved to be very useful to assess and diagnose the primary site in metastatic tumors of the liver.