2018 Volume 57 Issue 4 Pages 223-229
Background : Anaplastic carcinoma of the thyroid with a rhabdoid phenotype is extremely rare. Herein, we report a case of this tumor, together with the findings of aspiration cytology and immunocytochemistry using the cell transfer technique, as well as the histologic, immunohistochemical and electron-microscopic findings.
Case : An 80-year-old man noticed a subcutaneous mass in the left elbow. From the biopsy findings, the lesion was suspected as a metastatic tumor. Computed tomography demonstrated a large thyroid mass extending from the right lobe to the isthmus. In aspiration cytology, loosely adhesive, pleomorphic tumor cells with bizarre nuclei were seen, along with rhabdoid cells with eccentric nuclei possessing “hyaline-like” inclusion bodies in the cytoplasm. Immunocytochemistry using the cell transfer technique revealed positive staining of the tumor cells for cytokeratin and vimentin, and the “hyaline-like” inclusion bodies, in particular, were strongly positive for both. Histologically, most of the tumor cells consisted of anaplastic carcinoma cells, admixed with rhabdoid cells. In addition, typical papillary carcinoma was found in a part of the tumor. Electron-microscopically, the tumor cells with eccentric nuclei revealed aggregation of abundant intermediate filaments in the cytoplasm, confirming that they were rhabdoid cells.
Conclusion : Immunocytochemistry with the use of the cell transfer technique was useful for the diagnosis of anaplastic thyroid carcinoma with a rhabdoid phenotype in the present case.
