Flow Cytometric Analysis of DNA Content in Hürthle Cell Adenomas and Carcinomas of the Thyroid

Abstract

Paraffin-embedded surgical biopsy material from 17 Hürthle cell tumors of the thyroid was examined for DNA content by flow cytometry to assess the diagnostic and prognostic utility of ploidy determinations in these rare tumors. Both adenomas (11 cases) and carcinomas (6 cases) were studied. As a control for methods, ten randomly selected normal autopsy thyroids were analyzed, all of which demonstrated normal diploid DNA content. Among the Hürthle cell tumors, however, aneuploid peaks were present in six adenomas (55%) and in four carcinomas (67%). Similarly, polyploid DNA peaks in the absence of other aneuploid peaks were present in two adenomas and two carcinomas (18% and 33%, respectively). These findings demonstrate the limited value of aneuploidy or polyploidy as diagnostic features for malignancy in Hürthle cell tumors of the thyroid. As for prognosis, there does not appear to be any unfavorable prognostic significance for abnormal DNA content in histologically benign Hürthle cell tumors treated by surgical excision because no metastases or recurrences occurred in this group at a mean disease-free follow-up of 50 +/- 19 months for six aneuploid lesions and 19 +/- 7 months for two polyploid adenomas. Preliminary data suggest that aneuploidy may, however, have an important prognostic value for histologically defined Hürthle cell carcinomas, because the only patient to die from the tumor in this series had an aneuploid Hürthle carcinoma. Thus, the authors' data indicate that the diagnostic utility of DNA content in Hürthle cell tumors is extremely limited and that there does not appear to be any negative prognostic significance for aneuploidy in histologically defined Hürthle cell adenomas.

Differential Diagnosis of Hürthle Cell Neoplasms on Fine Needle Aspirates

“…17,25,[44][45][46][47][48]52,66,68,69,77 Some of the earlier morphometric studies, which found significant differences in nuclear features between follicular adenomas and follicular carcinomas, may have included cases of the follicular variant of papillary carcinoma, an entity that has become generally accepted only more recently. A similar lack of discrimination was found in DNA quantitation studies, which have shown a large overlap in aneuploidy rates between Hürthle cell adenomas and carcinomas 6,9,11,67,81 as well as between follicular adenomas and carcinomas. 81 The results of this study, together with the recent promising results obtained with argyrophilic nucleolar organizer regions quantitation in follicular neoplasms 16,38,63,71 may indicate that more diagnostic information can be gained by careful study of the number, size and shape of the nucleoli than from such features such as nuclear size, variation in nuclear size, nuclear irregularity and nucleocytoplasmic ratio, which have traditionally received more attention.…”

Hürthle cell tumours of the thyroid. A review with emphasis on mitochondrial abnormalities with clinical relevance

“…The same is true of the aneuploid DNA content, which appears to be common to benign and malignant Hürthle cell and to oxyphilic cell tumours in the different settings [5,48,60].…”

Thyroid Cancer: 1999 Update and Evaluation of Solitary Thyroid Nodules

“…Diploid nuclear DNA content is associated with a benign clinical course, even when other criteria for malignancy are present. 116,[127][128][129][130] The role of FNA biopsy in establishing the diagnosis of Hurthle cell lesions has been addressed in a number of studies. 118,125,131 In summary, these all show that the distinction between benign and malignant Hurthle cell neoplasms based on cytopathology alone probably cannot be made with a high degree of accuracy.…”