Cytodiagnosis of benign and malignant h�rthle cell lesions of the thyroid by fine-needle aspiration biopsy

Abstract

Eighty‐two Hürthle cell (HC) lesions of the thyroid with cytologic evaluation by fine‐needle aspiration biopsy (FNAB) were reviewed. In 17 cases the FNAB was not diagnostic because the fine‐needle aspirates (FNAs) were too scanty in cellularity. Among the remaining 65 lesions, there were 45 HC adenomas (HCAs), six non‐neoplastic HC nodules (NHCNs), 10 primary HC carcinomas (HCCs), and four metastatic HCCs. Forty‐four HCAs were diagnosed as HC tumor (HCT), and one HCA was wrongly diagnosed as medullary carcinoma. All six NHCNs were wrongly diagnosed as HCT. Of 10 primary HCCs, three were diagnosed as HCT and seven as suspected HCC. Four metastatic HCCs were correctly diagnosed. The FNAs from 38 HCAs and four NHCNs were predominantly composed of large monomorphic HCs with oval nuclei, inconspicuous nucleoli, and abundant, well‐defined, granular cytoplasm present singly, in acinar arrangement, and in monolayered sheets of variable sizes. Nuclear pleomorphism and prominent nucleoli were noted in seven HCAs and two NHCNs. Occasional small syncytial tumor cell clusters (STCCs) were noted in six cases, and a few naked tumor cell nuclei (NTCN) were observed in 16 cases. The FNAs from 14 HCCs were hypercellular. In all cases tumor cells were relatively small and showed monomorphic or pleomorphic nuclei, prominent nucleoli, and ill‐defined cytoplasm. STCCs of variable sizes were present in abundance in 10 cases, and numerous NTCN were noted in 12 cases. In two HCCs, the tumor cells with well‐defined cytoplasm were present singly and in cohesive sheets, and no STCCs or NTCN were observed. Thus, the presence of small tumor cells with ill‐defined cytoplasm and prominent nucleoli in syncytial clusters and abundant NTCN in the FNA of a thyroid nodule should alert the observer about the strong possibility of an HCC. Diagn. Cytopathol. 1999;20:261–265. © 1999 Wiley‐Liss, Inc.

The Significance of Hürthle Cells in Thyroid Disease

“…However, benign adenomas may demonstrate aneuploidy and cancers may be diploid. Neither flow cytometry nor analysis of cellular atypia has been proven to be able to discriminate between benign and malignant HCNs [9, 29,38].…”

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“…A hyperplastic Hurthle cell nodule in a Hashimoto thyroiditis or in a multinodular colloid goiter and a Hurthle cell neoplasm display similar cytologic findings [22-25,37,38]. The presence of numerous lymphocytes or a large amount of thick colloid material in the needle aspirate may indicate a hyperplastic Hurthle cell nodule in Hashimoto disease or a multinodular colloid goiter, respectively [38].…”

“…A hyperplastic Hurthle cell nodule in a Hashimoto thyroiditis or in a multinodular colloid goiter and a Hurthle cell neoplasm display similar cytologic findings [22-25,37,38]. The presence of numerous lymphocytes or a large amount of thick colloid material in the needle aspirate may indicate a hyperplastic Hurthle cell nodule in Hashimoto disease or a multinodular colloid goiter, respectively [38]. Hurthle cell adenoma and carcinoma usually show similar cytologic findings that are characterized by sheets and clusters of polygonal epithelial cells with abundant, granular, eosinophilic or basophilic cytoplasm, oval nuclei with regular nuclear contours and conspicuous or inconspicuous nucleoli [22-25] (Figs.…”

“…6 and 7). The presence of syncytial clusters of Hurthle cells with or without prominent nuclei [25] and abundant naked tumor cell nuclei has been reported to be a feature of Hurthle cell carcinoma [38]. …”

“…When a Hurthle cell lesion is detected by FNA, surgical excision is usually indicated for further histologic study [38]. Thyroid Hurthle cell lesions fall into the cytodiagnostic category of indeterminate lesions or suspected malignant lesions [14,15,22], and 13% of Hurthle cell lesions were malignant in one large series [12].…”