Anaplastic thyroid carcinoma is an infrequent, but aggressive fatal subtype of thyroid cancer. The osteoclastic variant of anaplastic carcinoma is a rare subtype of anaplastic carcinoma with rare cases reported in the literature. Molecular targeted therapies have emerged for the anaplastic carcinoma, necessitating accurate pathologic diagnosis with additional ancillary testing for directing clinical management. We present here the cytological diagnosis of an anaplastic thyroid carcinoma-osteoclastic variant on fine-needle aspiration (FNA), with emphasis on the novelty of utilizing the least invasive procedure (aspiration cytology) for rendering pathological diagnosis as well as identifying potential prognostic markers for targeted immunotherapy.anaplastic carcinoma, cytology diagnosis of thyroid carcinoma, osteoclastic variant, osteoclastlike giant cells, PD-L1 in thyroid carcinoma
| INTRODUCTIONAnaplastic (undifferentiated) thyroid carcinoma (ATC) is a highly malignant tumor, accounting 2%-5% of all thyroid malignancies. 1The tumor mostly presents in elderly women with a rapidly enlarging neck mass and extrathyroidal extension present in most cases.Many subtypes of anaplastic carcinoma have been reported including spindle cell/sarcomatoid, squamous, pleomorphic, angiomatoid, rhabdoid, paucicellular, as well as osteoclastic variants. 2,3 Large numbers of multinucleated, non-neoplastic, osteoclast-like giant cells intermingled with a high-grade malignant cell population characterizes the osteoclastic variant of ATC. ATC has a grave overall prognosis with a poor response to multimodality therapy. However, recent advances in genomic mutational studies suggest that this tumor may respond to targeted therapies including multikinasetargeted inhibitors on BRAF mutation and PD-L1 expression. 4 We hereby report a case of osteoclastic variant of ATC, diagnosed by fine-needle aspiration (FNA) including molecular marker studies using cytology material.
| CASE REPORTAn 81-year-old female patient was referred for the evaluation of a left neck mass with complaints of difficulty in throat clearing, hoarseness, and weight loss. She denied other symptoms like dysphagia or dyspnea. The computed tomogram (CT) of neck demonstrated a large 6.7 Â 4.6 Â 4.0 cm heterogeneous multi-lobated tumor appearing at the superior left thyroid displacing the hypopharynx and larynx, laterally on neck vasculature with narrowing, invasion, and tumor thrombus in the left internal jugular vein. The FDG PET/CT showed an intensely avid left neck mass with innumerable cervical lymph node metastasis and multifocal bilateral intensely avid metastatic pulmonary nodules (Figure 1). FNA was performed on the neck mass. Air-dried smears, alcoholfixed smears, and cellblock cytology slides were prepared and stained by Diff-Quik, Pap, and Hematoxylin & Eosin methods, respectively. Surekha Bantumilli and Lee-Ching Zhu contributed equally to this work.