Case ReportOpen Access

Features of Anaplastic Thyroid Carcinoma on Liquid-based Cytology and Pitfalls in the Cytologic Diagnosis of Thyroid Tumors with Spindle Cells: A Case Report

Volume 2 - Issue 4

Songmi Noh, Eunah Shin, Jeong Yun Shim and Ji Young Kim*

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- Department of Pathology, CHA Gangnam Medical Center, CHA University, South Korea
*Corresponding author: Ji Young Kim, Department of Pathology, CHA Gangnam Medical Center, CHA University, Seoul, South Korea, 566, Nonhyon-ro, Gangnamgu, Seoul, 06135, South Korea

Received: February 10, 2018; Published: February 20, 2018

DOI: 10.26717/BJSTR.2018.02.000778

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Abstract

Anaplastic thyroid carcinoma (ATC) is a highly aggressive but rare thyroid malignancy. Cytologically it typically shows a mixture of three cell groups, i.e. spindle cells, giant cells, and squamoid/epithelioid cells. But, when it is composed predominantly of spindle cells, the diagnosis of ATC may not be robust. Here we report a case of thyroid anaplastic carcinoma predominantly composed of spindle cells with its cytologic features on liquid-based preparation. A 61-year old male visited our hospital with a 7cm-sized thyroid nodule detected on a regular checkup. The initial fine needle aspiration was unsuccessful showing only cystic fluid. The patient underwent radiofrequency ablation (RFA) with decrease in the size of the mass that, after six month, enlarged back again. Left lobectomy and isthmusectomy was performed. Liquid-based cytologic sample was prepared using the scraped material from the resected mass. Cytologically, the predominant cells were spindle cells, arranged in clusters or in single cells. They had enlarged nuclei with vesicular chromatin with minimal chromatic clumping. The nucleoli were small but prominent. Giant cells, squamoid cells, or large pleomorphic cells were not present. The background was slightly necrotic and degenerative. When a thyroid FNA from a thyroid nodule reveals spindle cells, differential diagnosis should include ATC, medullary carcinoma, other sarcomas, reactive fibrosis in Riedel’s thyroiditis, etc. The degree of cytologic atypia of the spindle cells, the presence of other components such as giant cells and squamoid/epithelioid cells, along with the immunohistochemical staining for calcitonin, CEA, PAX-8, and/or TTF-1 can readily differentiate ATC from others.

Keywords: Anaplastic thyroid carcinoma; Ablation therapy; Liquid-based cytology; Spindle cells

Abbreviations: ATC: Anaplastic Thyroid Carcinoma; RFA: Radio Frequency Ablation; SMA: Smooth Muscle Actin; SETTLE: Spine Cell Tumor with Thymus-Like Differentiation