Follicular neoplasms of the thyroid in men older than 50 years of age. A DNA flow cytometric study

Computerized Morphometric Study of Thyroid Follicular Carcinoma in Correlation with Known Prognostic Factors

This study investigates the correlation between computer-assisted nuclear morphometry and known prognostic factors in thyroid follicular carcinoma. Thirty-six patients with thyroid follicular carcinoma who underwent surgery between 1991 and 2001 were grouped according to sex, age, size of the primary lesion, the presence of vascular invasion, and metastases. Four nuclear parameters were measured and analyzed: mean nuclear area, mean nuclear perimeter, largest to smallest diameter ratio of the nuclei, and coefficient of variation of the nuclear area. Our results indicated that none of the chosen nuclear variables were significantly correlated with the prognostic factors studied. In conclusion, nuclear morphometry does not seem to correlate with known prognostic factors and cannot serve as an additional predicting factor for biologic behavior.

Expression of human telomerase reverse transcriptase in thyroid follicular neoplasms: an immunohistochemical study

Differential diagnosis of follicular adenoma (FA) and follicular carcinoma (FC) of the thyroid can be difficult in the routine practice of surgical pathology because the diagnosis of FC is strictly defined and determined by the presence of capsular and/or vascular invasion by the tumor. These features may be equivocal in the histologic sections. On the other hand, telomerase is expressed in many human cancers and is thought to contribute to their immortality. Human telomerase reverse transcriptase (hTERT) is the major determinant of human telomerase activity, and its expression is suggestive of capacity for unlimited replication. This case-control study examined the expression of hTERT using immunohistochemistry in 36 thyroid FC and 36 FA from patients who were matched by age and sex. The aim was to investigate the value of immunohistochemical staining for hTERT in the differential diagnosis of follicular neoplasms. The results revealed 23 cases of FC and 14 cases of FA that showed high expression of hTERT, with moderate to strong immunoreactivity. The remaining cases showed weak or negative staining. The difference between FA and FC was statistically significant (p < 0.05). In conclusion, immunohistochemical staining for hTERT can be considered an ancillary marker for differential diagnosis of FA and FC.

Computer-assisted cell morphometry and ploidy analysis in the assessment of thyroid follicular neoplasms

Conventional cytology cannot discriminate between benign and malignant follicular neoplasms. Our study evaluated the diagnostic role of computer-assisted image analysis in the presurgical assessment of thyroid follicular neoplasms. Fifty-eight patients (14 males, 44 females, age range, 45-75 years) who underwent surgery for cytologic diagnosis of thyroid follicular neoplasm were studied. All patients were first evaluated on clinical grounds and assigned a high/low suspicion of malignancy on the basis of gender, age, and nodule size. Cell image analysis was subsequently performed using a Cytometrica BYK Gulden microscope image processor on Feulgen-stained thyroid cytologic smears. A different population of 50 benign and 50 malignant, histologically evaluated nodules was studied in order to establish image analysis criteria suggestive of thyroid malignancy. Ploidy histogram, proliferation index (PI), nuclear area coefficient of variation (NACV), and anisocariosis ratio (AR) were studied. Thyroid cancer was diagnosed in 16 of 58 follicular neoplasms. Only 7 of these lesions were clinically suspicious (43.7%), whereas 14 of 16 (87.5%) malignant tumors were identified by image analysis. Positive and negative predictive values of image analysis versus clinical evaluation were 46.6% versus 30.4% and 92.8% versus 74.3%, respectively. The distribution of ploidy pattern was different in benign versus malignant follicular neoplasms (chi2 8.25, p = 0.016), malignant lesions showing an increased frequency of heteroclonal aneuploid DNA content (37.5% vs. 7.1%). Increased PI (mean +/- standard deviation (SD) = 11.3 +/- 5.7 vs. 7.1 +/- 6.1; p < 0.01) and NACV (mean +/- SD = 25.28 +/- 1.89 vs. 20.14 0.91; p < 0.01) levels were also observed in malignant follicular neoplasms. In conclusion, computer-assisted image analysis may profitably support clinical evaluation in the assessment of thyroid follicular neoplasms.

A clinicopathologic study of minimally invasive follicular carcinoma of the thyroid gland with a review of the English literature

BACKGROUND

The criteria for minimally invasive (low grade) follicular carcinoma of the thyroid (MI) remain controversial, often resulting in unnecessary treatment.

METHODS

The records of 130 patients with minimally invasive (MI) follicular thyroid carcinoma were retrieved from the files of the Endocrine Tumor Registry of the Armed Forces Institute of Pathology.

RESULTS

Ninety-five patients were confirmed to have MI based on the authors' criteria of small-to-medium vessel invasion, capsular invasion of up to full thickness, no parenchymal tumor extension, and no tumor necrosis (patients with oxyphilic tumors were excluded). The remaining 35 patients had tumors that were reclassified as "not low grade" based on large vessel invasion, extension into parenchyma, and tumor necrosis (oxyphilic cases excluded). The MI patients included 67 women and 28 men, ages 20-95 years (average, 42.0 years). Nearly all patients presented with a thyroid mass (n = 90 patients). The mean tumor size was 2.8 cm. Histologic features examined for tumor classification included cellularity, capsule nature, capsular invasion, vascular invasion, extension into parenchyma, cytoplasmic oxyphilia, mitotic activity, and necrosis. All patients were treated with surgical excision. Adjuvant radioactive iodine therapy was performed in 24 patients. Five patients developed recurrent disease: four were alive or had died without evidence of disease after additional treatment (mean, 18.1 years), and one patient died with disease (MI tumor) at 15.1 years. All of the remaining patients were disease free (mean follow-up, 16.5 years).

CONCLUSIONS

There are reproducible histologic criteria to diagnose patients with MI follicular carcinoma. The overall excellent long term prognosis and a good patient outcome suggests that no additional surgery is necessary.

Measurement of vascularity as a diagnostic and prognostic tool for well differentiated thyroid tumours: comparison of different methods of assessing vascularity

AIMS

To determine whether the measurement of vascularity can be used to differentiate follicular adenomas from follicular carcinomas or to reflect the prognosis of follicular carcinomas and papillary carcinomas of the thyroid gland, and to compare four methods of assessing vascularity.

METHODS

Tissue sections from 26 papillary carcinomas, 15 follicular adenomas, and 15 follicular carcinomas were stained with an antibody to CD34. A computerised image analysis system was used to calculate, for each tumour, mean endothelial areas and the mean endothelium to tumour epithelial nucleus area ratio from 10 systematically selected fields across one dimension of the tumour ("systematic field" analysis) or from the three most vascularised fields of the tumour ("hot spot" analysis). A European Organisation for Research on Treatment of Cancer (EORTC) prognostic index was calculated for each papillary carcinoma and follicular carcinoma.

RESULTS

Significant differences in vascularity between the three tumour groups could only be shown by comparing mean endothelial area values measured from hot spots. While the hot spot median mean endothelial area of follicular carcinomas was significantly greater than that of follicular adenomas, there was a large overlap between the two groups. For follicular carcinomas, higher hot spot mean endothelial area values were related to worse prognosis as indicated by the EORTC prognostic indices. No association between vascularity and prognosis was found for the papillary carcinomas, regardless of the method of assessing vascularity.

CONCLUSIONS

Measuring endothelial area from hot spots using a computerised image analysis system is a sensitive method of assessing the vascularity of thyroid tumours. While vascularity measurement cannot be recommended as a practical tool for differentiating between malignant and benign follicular tumours, the suggestion that vascularity may reflect prognosis for follicular carcinomas deserves further study.

Proliferation Markers and Their Uses in the Study of Endocrine Tumors

A growing body of literature supports the view that the proliferative activity (PA) of tumor cells is an important prognostic indicator for a variety of different tumors. We examined the role of PA in diagnosis and prediction or malignancy of endocrine tumors (ETs) of pituitary gland, pancreas, thyroid, parathyroid glands, adrenal glands, paraganglia, gastroenteric tract, and lung. The data in the literature indicate that the assessment of PA is not a diagnostic indicator of malignancy especially at the individual case level, whereas it can be useful for identifying subsets of malignant tumors with different aggressiveness potential, as well as for choosing therapeutic options in metatstatic lesions. We hope that, in the near future, multiparametric approaches including PA markers, cell growth and differentiation factors, and oncogenes will yield valuable information for diagnosis and prognosis of ETs also in individual cases.

DNA flow cytometric analysis of neuroblastoma: distinction of tetraploidy subset

Neuroblastoma has several characteristics that differentiate it from other adult malignancies. The ploidy pattern of neuroblastoma has been shown to be related to prognosis. Specifically, a DNA diploidy pattern is associated with a poorer outcome, and an aneuploidy pattern is associated with a better outcome. A tetraploidy pattern has also been identified; however, there is little information regarding this pattern. To examine the properties of neuroblastoma according to these DNA ploidy patterns, the authors performed flow cytometric analysis (retrospectively) for 61 neuroblastoma cases, using paraffin-embedded tissues. Fifty-six of the cases had analyzable results. Calculated DNA indices (DI) ranged from 1.0 to 2.30. The 56 cases were divided into three groups according to DI: diploid (DI = 1.0 to 1.17, n = 19), aneuploid (DI = 1.25 to 1.75, n = 26), and tetraploid (DI = 1.81 to 2.30, n = 11) groups. Compared with the aneuploid group, the diploid group had a stronger correlation with older patient age (> or = 1 year) (P < .01), more advanced clinical stage (III, IV) (P < .01), and poorer prognosis (P < .001). The tetraploid group had properties that were statistically similar to those of the diploid group (P < .05, P < .05, P < .001, respectively). These findings indicate that a subset of DNA tetraploid is present in neuroblastoma, and this subset, which may have clinical and biological characteristics similar to those of the DNA diploid group, should be distinguished from DNA aneuploidy.

A comparative study of flow cytometry and histopathologic findings in thyroid follicular carcinomas and adenomas

As a possible diagnostic aid in the often difficult histopathologic distinction of thyroid follicular carcinomas from adenomas based on invasion most flow cytometry studies have indicated a higher aneuploidy incidence in carcinomas. However, these reports often are difficult to analyze mainly due to nonuniformity of pathologic diagnostic criteria. The present study compares the flow cytometry results of 65 follicular tumors with pathologic findings based on the World Health Organization's specific diagnostic and staging criteria. Aneuploidy was significantly higher in the 28 cancers than in the 27 hypercellular (fetal and embryonal) adenomas (57% v 22%; P = .02). There was a high percentage of aneuploidy (75%; nine of 12 cases) in the widely invasive follicular carcinomas, compared with 40% (six of 15 cases) in the minimally invasive carcinomas, 22% (six of 27 cases) in the hypercellular adenomas, and 10% (one of 10 cases) in the normofollicular or macrofollicular adenomas. However, aneuploidy was not significantly different between the most difficult differential histopathologic diagnoses of minimally invasive follicular carcinoma (40%; six of 15 cases) and hypercellular adenoma (22%; six of 27 cases) (P = .12). Other data included relatively high frequencies of aneuploidy in hypercellular adenomas (29%; six of 21 cases) and diploid status of carcinomas (36%; 12 of 33 cases). In summary, although the overall findings show a trend toward increasing aneuploidy from well-differentiated and hypercellular adenomas to minimally and widely invasive follicular carcinomas, the aneuploidy data are inconsistent and indicative of its nonspecificity and limited diagnostic usefulness.

Ploidy level and proliferative activity measurements in a series of 407 thyroid tumors or other pathologic conditions

This study describes the ploidy level and proliferation rate in a series of 74 multinodular goiters (MNGs), 17 cases of Hashimoto's disease, 33 cases of Basedow's disease, 113 adenomas, 139 primary carcinomas, and 31 cervical lymph node metastases from 376 patients. Both ploidy level and proliferation rate were assessed by digital cell image analyses of Feulgen-stained nuclei from formalin-fixed, paraffin-embedded tissues. The ploidy level of each sample was assessed using both its DNA index and its DNA histogram type. The proliferation index assessments corresponded to the determination of the proportion of cells in the S-phase fraction. The data reveal that the proportion of aneuploid cases increases according to the following sequence: simple MNGs and normomacrovesicular adenomas-->MNGs with adenomatous hyperplasia and microvesicular adenomas and Hürthle cell adenomas-->papillary and Hürthle cell carcinomas-->follicular and medullary carcinomas-->anaplastic carcinomas. This suggests the preneoplastic nature of the microvesicular adenomas and even of MNGs with adenomatous hyperplasia. The ploidy levels of 99% of the 407 cases of the thyroid tumor series could be described using six DNA histogram types: diploid, hyperdiploid, triploid, hypertriploid, tetraploid, and polymorphic. It was possible to assess the proliferation rate of 279 samples. The results show that a significantly higher proportion of malignant compared with benign thyroid tumors (35.5% v 10.5%, respectively) exhibited a proliferation index higher than 5%, and that, whether benign or malignant, the hypertriploid thyroid tumors proliferated significantly less than the nonhypertriploid thyroid tumors.

Predictive value of fine-needle aspiration of the thyroid in the classification of follicular lesions

BACKGROUND

Fine-needle aspiration has been less valuable in the diagnosis of follicular lesions than for other neoplasms of the thyroid. It has been observed that follicular carcinoma is found in microfollicular, but not macrofollicular lesions, and this has served as a guide to management for many surgeons. The authors attempted to determine what cytologic parameters might usefully distinguish these types of follicular lesion.

METHODS

The histologic findings and cytology of 56 thyroid lobectomies for follicular lesions that had adequate preoperative fine-needle aspiration of the thyroid (FNAT) were reviewed. Histologic specimens were classified into macrofollicular, mixed, and microfollicular groups. Cytologic features examined included the presence of colloid, irregularity of cell arrangements within groups, the presence and size of flat and folded cell sheets, three-dimensional clusters, and microfollicles and macrofollicles.

RESULTS

Of the histologic specimens, 15 were preponderantly (> 70%) microfollicular, 19 were mixed, and 22 were predominantly (> 70%) macrofollicular. Three cytologic features were useful in their distinction: none of the predominantly microfollicular but 24% of the mixed and predominantly macrofollicular had abundant colloid (P = 0.048). Likewise, none of the predominantly microfollicular but 27% of the mixed and predominantly macrofollicular had large follicles (P = 0.026). Finally, 73% of the predominantly microfollicular but only 37% of the mixed and predominantly macrofollicular showed irregularity or crowding of cells in groups (P = 0.018).

CONCLUSIONS

Used in combination, abundant colloid, regular spacing, and large follicles are helpful in distinguishing macrofollicular and mixed lesions from microfollicular ones, which have a higher malignant potential.

Atypical adenoma of the thyroid. A clinicopathologic and flow cytometric DNA study in comparison with other follicular neoplasms

A clinicopathologic and DNA flow cytometric study was performed on seven patients (three males, four females) with atypical adenoma of the thyroid gland, using formalin-fixed paraffin-embedded tissues. The results were compared with those of 30 follicular adenomas and 13 follicular carcinomas. The patients ranged in age from 32 to 74 years (mean; 55.8 years), and the mean follow-up period was 11.0 years. All patients except two who died of other diseases were free of thyroid disease after initial surgery. It showed that there was no evidence of clinical cancer in this follow-up study of patients operated on for atypical adenomas. Four of the atypical adenomas were diploid, two were aneuploid, and one was tetraploid. Twenty-seven of the 30 follicular adenomas were diploid. Three patients with aneuploid follicular adenoma were free of disease. Of the 13 follicular carcinomas with a mean follow-up period of 6.9 years, five were diploid, seven were aneuploid, and one was tetraploid. Two patients with aneuploid follicular carcinoma and one with diploid carcinoma developed lung metastases, and one patient each with diploid and aneuploid follicular carcinoma died of disease. There was no significant correlation between histologic features, ploidy status and prognosis among follicular carcinomas. The results of this study suggest that DNA flow cytometric analysis is not a useful tool for predicting the clinical behavior of follicular neoplasms.

Follicular tumors of the thyroid gland: diagnosis, clinical aspects and nuclear DNA analysis

From 1985 to 1990, 169 patients underwent surgery for follicular thyroid tumors at the Department of Surgery, Karolinska Hospital, Stockholm, Sweden. Nine of the patients had tumors which were diagnosed as follicular carcinoma, 4 of whom had recurrences in the neck region. In 6 of the patients the carcinomas were diagnosed as widely invasive and in 3 patients as minimally invasive. Of the 160 patients with follicular adenomas, 21 adenomas were of oxyphil type ("Hürthle" adenomas), 17 adenomas were diagnosed as "atypical", and 6 adenomas were classified as being both "atypical" and having oxyphil cell differentiation. The nuclear DNA content was measured with image cytometry and/or flow cytometry. Six of the 9 carcinomas were euploid and 3 were aneuploid. In the adenoma group, 32 (20%) were aneuploid. Thus 38% of all adenomas showed atypical cellular features, oxyphil cell differentiation, and/or aneuploid nuclear DNA pattern. None of the patients with adenomas have shown any sign of recurrence. In the present prospective study, the nuclear DNA content could not discriminate between a benign and a malignant follicular tumor, and was of limited value in predicting prognosis in the patients with follicular carcinoma. Still, the best way to establish a diagnosis and to predict prognosis is to surgically remove the follicular tumor for a proper histopathological examination.

The study of endocrine tumors by flow and image cytometry

Both DNA flow and image cytometry are methods that can be used for the quantitative determination of cellular DNA content. Objective, quantitative analysis of cellular morphology can also be obtained using image cytometry. Data thus generated have been shown to be of diagnostic and prognostic use in the study of many solid tumors and would be of particular value in the evaluation of endocrine tumors that show a poor correlation between their histology and biological behavior. The main application of these techniques to endocrine tumors has been in the analysis of thyroid nodules, although a limited number of studies of parathyroid, pituitary, adrenal, and pancreatic neuroendocrine tumors and tumors of the dispersed neuroendocrine system have been reported. Review of these studies shows that in the endocrine organs DNA and morphometric measurements have a very limited role in the diagnosis of individual cases, but are important as prognostic variables. The high incidence of abnormal DNA content in histologically benign lesions of the endocrine glands has important biological implications. Further investigation of this phenomenon may help to elucidate the process of endocrine tumorigenesis.