Value of quantitative nucleolar features in the preoperative cytological diagnosis of follicular neoplasias of the thyroid.

Nucleolar prevalence, size, and outline were investigated on cytological material from cold thyroid nodules obtained by fine needle aspiration. The percentage of nucleolated nuclei in follicular adenoma (32 cases) was less than in follicular carcinoma (26 cases). In adenoma most nuclei contained one nucleolus, and nuclei with two or more nucleoli were less common than in carcinoma where most cases showed the highest nucleolar diameter values. There was some overlap between adenomas and carcinomas, however, when the mean of the 10 largest values of the major nucleolar diameter was considered. In follicular carcinoma the percentage of marginated nucleoli--that is, those touching the nuclear membrane--was, in general, greater than 20%; in adenoma the values were equal to or lower than 16%. The overlap index showed that the percentages of marginated nucleoli and nucleolated nuclei are the two best discriminatory features between adenoma and carcinoma.     

Histomorphometry in paraffin sections of thyroid tumors.

Planimetric features of cell nuclei in paraffin-embedded histological sections of benign and malignant thyroid tumors, as well as normal thyroid tissue as control, were determined by means of a semiautomatic system. The main aim was to objectify possible quantitative differences between adenomas and carcinomas of the thyroid gland, which had recently been reported by several authors. For each nuclear profile, the area, the maximum diameter as well as two form factors were calculated. Statistical analyses of morphometric differences between normal controls, oxyphilic adenomas and carcinomas, and between follicular adenomas and carcinomas were performed using the T-test, a multivariate test, and a discriminant analysis. The tests revealed significant differences between controls and all other groups. The most striking result, however, was the total discrimination between follicular adenomas and carcinomas, with no false reclassification. Carcinomas had a higher mean nuclear area and diameter and a lower form factor. A similar reliability of discrimination could be obtained by comparing these morphometric values in oxyphilic adenomas and carcinomas. When using a test set of 9 cases (4 adenomas, 5 carcinomas), only one adenoma was falsely reclassified as a carcinoma by the discriminant analysis. Our results thus allow the conclusion that planimetric nuclear measurements indeed seem to be useful for the objectivation of cytomorphologic differences between adenomas and carcinomas of the thyroid gland.     

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.     

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. Acta Pathol Jpn 42: 632–638, 1992.     

Fetal adenomas and minimally invasive follicular carcinomas of the thyroid frequently display a triploid or near triploid DNA pattern

The ploidy pattern and the percentage of S-phase cells were investigated by means of flow cytometry using fresh or frozen samples in a series of 143 tumors and tumor-like lesions of the thyroid in an attempt to find whether there is any relationship between the histological characteristics of the lesions and their DNA content. The percentages of aneuploidy cases per category were: nodular goiter, 18.5% (15/81); fetal adenoma (including cases with trabecular/solid growth pattern), 58.3% (14/24); follicular adenoma other than fetal adenoma, 0% (0/18); papillary carcinoma, 11.1% (1/9); and minimally invasive follicular carcinoma, 57.1% (4/7). Regardless of the histological category, aneuploid lesions had a significantly higher (P < 0.001) percentage of S-phase cells (7.3%) than diploid lesions (4.1%). All the six cases with a DNA content within the triploid range were fetal adenomas, but one was a follicular carcinoma displaying a fetal adenoma-like growth pattern. The other three follicular carcinomas with an aneuploid DNA pattern also displayed foci of fetal adenoma-like growth pattern. Image cytometry of the four aneuploid follicular carcinomas showed similar DNA indexes in the peripheral, invasive foci of the lesions and in the central fetal adenoma-like areas. These results demonstrate that aneuploidy in benign tumors is restricted to adenomas displaying a fetal or fetal/embryonal growth pattern and support the concept that chromosome instability is a major pathway of tumorigenesis in thyroid follicular neoplasms.     

Cytokeratin 19 and galectin-3 immunohistochemistry in the differential diagnosis of solitary thyroid nodules

AIMS: The immunohistochemical expression of cytokeratin 19 (CK 19) and galectin-3 was evaluated in 69 thyroid lesions to assess their potential as markers in the diagnosis and classification of thyroid malignancy. The following were studied: 26 cases of papillary carcinoma, 12 of follicular carcinoma, 20 follicular adenomas, two medullary carcinomas, one anaplastic carcinoma and eight multinodular goitres. METHODS AND RESULTS: Formalin-fixed paraffin-embedded thyroid tissues were stained immunohistochemically for both CK 19 and galectin-3. CK 19 expression was found in all 26 papillary carcinomas, five of 12 follicular carcinomas, two of two medullary carcinomas and one case of anaplastic carcinoma. Only five of 20 follicular adenomas were positive for CK 19, and this was in a focal distribution. Two of eight multinodular goitres stained focally positive. Galectin-3 expression was found in 22 of 26 papillary carcinomas, 12 of 12 follicular carcinomas and one of two cases of medullary carcinoma. Only two of 20 follicular adenomas were positive. Three of eight multinodular goitres showed focal galectin-3 expression. CONCLUSIONS: Our findings suggest that the immunohistochemical localization of CK 19 and of galectin-3 is a useful adjunct to the histopathological diagnosis of a solitary thyroid lesion. The expression of CK 19 favours a diagnosis of papillary carcinoma in all its variant patterns. Galectin-3 may serve as a marker for the recognition of follicular carcinoma, particularly the minimally invasive form.     

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

The clinical behavior of follicular neoplasms of the thyroid in elderly men can be difficult to predict on histologic grounds alone. To assess the usefulness of DNA flow cytometry in predicting the metastatic potential of these tumors, the authors studied 44 primary and metastatic follicular neoplasms of the thyroid by DNA flow cytometry of paraffin-embedded tissue. The neoplasms were obtained from 44 men ranging in age from 50 to 79 years (mean, 60). There were 29 follicular adenomas, 11 primary follicular carcinomas (neoplasms with capsular and/or vascular invasion), and 4 metastatic follicular carcinomas. Follow-up information was available on 40 of the 44 patients. The mean follow-up was 114 months. Twenty-five of the 29 follicular adenomas had a diploid DNA content, 2 (7%) were tetraploid, and the DNA histograms on 2 were not interpretable. All patients with follicular adenomas had no evidence of disease (NED) at last follow-up. Eight of the 11 primary follicular carcinomas were diploid. Six of these patients had NED, one died with carcinoma at 82 months, and no follow-up was available on one. Three (27%) of the primary follicular carcinomas were aneuploid or tetraploid. Two of these patients had NED, and the third died with carcinoma 84 months after diagnosis. Two of the four metastatic follicular carcinomas were diploid and two (50%) were aneuploid or tetraploid. One of the two patients with diploid metastatic follicular carcinomas died with carcinoma, as did one of the two patients with aneuploid metastatic follicular carcinomas. These results suggest the following: (1) follicular carcinomas are more likely to be aneuploid or tetraploid than are follicular adenomas; (2) follicular neoplasms without capsular or vascular invasion may include a small number of aneuploid or tetraploid tumors; and (3) DNA ploidy does not add to the prognostic value of histologic studies alone.     

“Cellular adenomatoid nodules” of the thyroid: Review of 219 fine-needle aspirates

We reviewed 219 consecutive thyroid aspirates previously diagnosed as “cellular adenomatoid nodule.” applying the criteria presented in this paper and reclassifying them as 146 adenomatoid nodules (AN), 31 cellular adenomatoid nodules (CELL-AN), 29 cellular adenomatoid nodules vs. follicular neoplasms (CELL-AN vs. FN), 5 follicular neoplasms (FN), 2 FN of oxyphilic cell type, 4 papillary carcinomas, and 2 chronic lymphocytic (Hashimoto's) thyroiditis. Of the 146 adenomatoid nodules, 14 occurred in multinodular goiters on histologic examination. Of the 31 CELL-AN, five had surgery: two were follicular adenomas, one was papillary carcinoma, and two were multinodular goiters. Of the 29 CELL-AN vs. FN, 11 had surgery: six were follicular adenomas, two were follicular carcinomas, two were multinodular goiters, and one was Hashimoto's thyroiditis. Surgery on four FN showed follicular adenomas (a fifth patient was lost to follow-up). Of the two FN of oxyphilic cell type, one was a multinodular goiter and the other a follicular adenoma with oxyphilic cells. Three of the four papillary carcinomas were confirmed histologically (one patient was lost to follow-up). Of the two cases showing Hashimoto's thyroiditis, one was diagnosed as FN on repeat aspiration and follicular carcinoma at surgery. After review, we identified 40 patients at higher risk of harboring a neoplasm and 31 with cellular adenomatoid nodules. Twenty-five underwent surgery with the above results. In the classification of follicular lesions of the thyroid by FNA, adherence to strict cytologic criteria helps identify those patients who will benefit most from surgery.     

Significance of argyrophilic proteins of the nucleolar organizer region in differentiation of benign and malignant growth of thyroid epithelial tumors]

Argyrophilic proteins of nucleolar organizers (NO) were measured in 47 benign (24 follicular and 8 atypical adenomas) and malignant (8 papillary and 7 follicular carcinomas) tumors. The content of argyrophilic NO proteins was significantly higher in malignant cells. The proportion of cells with at least 5 silver grains per cell was 16.8 and 22.8% in follicular and papillary carcinoma, respectively, and 3.2 and 12% in follicular and atypical adenoma, respectively. These data can be used as accessory signs in differential diagnosis.     

Follicular lesions of the thyroid: a retrospective study of 1,348 fine needle aspiration biopsies

Fine needle aspiration (FNA) has proven to be an effective tool in management of patients with thyroid nodules. However, the diagnosis of follicular patterned lesions can be challenging. The surgical and cytopathology computer database at a large referral medical center was searched for cases that had both cytologic and histologic thyroid accessions from January 2004 to November 2008. A total of 1,255 histologic thyroid specimens and 2,776 thyroid FNA biopsies were retrieved for review. Histologically, 272 overt malignancies were identified; 20 (7.4%) were follicular carcinomas. Cytologically, 1,348 cases were follicular-patterned lesions, comprising 1,044 cases of "benign follicular nodules" (BFN), 137 cases of "follicular lesions of undetermined significance" (FLUS), and 167 cases of "suspicious for follicular neoplasm" (SFN). Seventy-nine (7.5%) of BFN, 23 (16.8%) of FLUS, and 65 (38.9%) of SFN cases had histologic follow-up. Overt malignancy, a cystic papillary carcinoma, was identified histologically in only one case of BFN, for a negative predictive value of 98.7%. Overt malignancy was identified histologically in two cases of FLUS, both follicular variant of papillary carcinoma, for a positive predictive value of 8.7%. Overt malignancy was identified histologically in 14 cases of SFN, for a positive predictive value of 21.5%. Five follicular carcinomas were identified histologically in the SFN category, all minimally invasive. Incidental ("occult") papillary microcarcinoma were identified histologically in all three categories. In this study, the risk of overt malignancy increases from 1.3%, to 8.7%, to 21.5% for BFN, FLUS, and SFN, respectively. All follicular carcinomas identified histologically occurred in the SFN category and all were minimally invasive. Papillary microcarcinomas can occur in any of the three diagnostic categories.     

Multivariate karyometric approach in differential diagnosis of follicular thyroid neoplasms

 A retrospective analysis of 19 follicular adenomas, 12 minimally invasive follicular carcinomas and 3 widely invasive follicular carcinomas of the thyroid was performed on 5-μm-thick Feulgen-stained paraffin sections by means of a semiautomatic system for picture analysis. The major aim was to assess the potential of multiparameter karyometry for separation of the first two tumour types. Sixteen planimetric and densitometric features were defined in each case on 200–300 randomly selected nuclei and processed by a number of uni- and multivariate statistical methods. Despite predominantly significant ANOVA results a substantial overlap between tumour groups limited the practical usefulness of any karyometric feature alone. Factor and cluster analyses indicated independence of planimetric and densitometric parameters from each other, which was of crucial importance in finding an optimal subset of variables for discriminant analysis. The classification rule derived from the latter procedure was checked by the ”jack-knife” method, by classification of 3 widely invasive cancers and by hierarchical tumour clustering. Sensitivity and specificity of the model for detection of malignancy were 100% and 94.7%, respectively. A multivariate karyometric approach, when applied correctly, can be a useful tool for differentiation between follicular adenomas and minimally invasive follicular carcinomas of the thyroid. Received: 1 August 1997 / Accepted: 23 March 1998     

Immunohistochemical analysis of survivin expression in thyroid follicular adenoma and carcinoma.

Survivin is one of the 8 members of human inhibitor of apoptosis , which is differentially expressed in cancerous/transformed cells versus normal differentiated tissues. This retrospective study of thyroid histologic samples aimed to assess the clinical usefulness of survivin immunostaining for discrimination between follicular adenoma and carcinoma of thyroid. Immunohistochemical staining for survivin was performed on 41 lesions from patients who had undergone surgery for either follicular adenoma or carcinoma of thyroid. Survivin expression was significantly (P < 0.005) higher in the cases that received a diagnosis of carcinoma in comparison with follicular adenomas cases. Odds ratio of follicular carcinoma for survivin expression was 21.375 (95% CI: 3.283 to 139.177). Our results showed potential value of survivin in discrimination between follicular thyroid adenoma and follicular thyroid carcinoma. We conclude that survivin is a potential candidate for further investigation in the proper histologic diagnosis of thyroid cancers.     

Distribution of Leu-7 antigen (HNK-1) in thyroid tumors: its usefulness as a diagnostic marker for follicular and papillary carcinomas.

The reactivity of the anti-Leu-7 monoclonal antibody was tested in 39 neoplastic and nonneoplastic thyroid tissue specimens. These included eight colloid goiters, 14 follicular adenomas, nine papillary carcinomas, five follicular carcinomas, two medullary carcinomas, and one metastatic follicular carcinoma in bone. We observed strong cytoplasmic and/or cell membrane positivity in all follicular and papillary carcinomas, in both primary and metastatic tumors. However, the medullary thyroid carcinomas tested were negative. We also observed weak and only occasional staining with anti-Leu-7 antibody in colloid goiter and follicular adenomas. The staining in the benign thyroid lesions was usually focal, less than 10% of the cells; however, in cases of follicular and papillary carcinomas, both in primary and metastatic tumors, the staining was diffuse and strong. Some of the colloid material in colloid goiters and follicular adenomas showed faint homogenous staining with anti-Leu-7 antibody. Our findings suggest that anti-Leu-7 monoclonal antibody is a marker that may facilitate the differentiation between benign and malignant thyroid lesions, with the exception of medullary carcinoma. In addition, caution should be taken when using this antibody to diagnose metastatic lesions, as other metastatic carcinomas have also been reported to be positive. This antibody should be used in conjunction with a panel of antisera to complement a morphologic diagnosis.     

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.     

Thyroid tumors with a follicular growth pattern: problems in differential diagnosis

Tumors of the thyroid characterized by a follicular growth pattern constitute the most common type of lesion of this organ encountered by pathologists. The vast majority of such lesions do not pose difficulties for histopathologic interpretation. A subset of these tumors, however, can represent a serious challenge for diagnosis. Thyroid tumors with a follicular growth pattern include a broad range of lesions that range from benign, hyperplastic nodules to follicular adenomas to follicular carcinomas. In addition, other types of tumors belonging in separate diagnostic categories can also present histologically with a follicular growth pattern, including the follicular variant of papillary thyroid carcinoma and medullary carcinoma. The histologic features and diagnostic criteria used for distinguishing among these conditions can often be subtle and subjective.     

Thyroid tumors: cytomorphology of follicular neoplasms

From 2,012 fine-needle aspirations (FNA), performed by us between the years 1984 and 1988, we present a detailed cytomorphologic analysis of 95 cases that were diagnosed as neoplastic on histology and/or cytology and those that received an equivocal cytodiagnosis. Discussed are 37 lesions that have been diagnosed on cytology and/or histopathology as follicular neoplasms. In this group, there were 22 cases of histologically proven follicular carcinoma and 11 follicular adenomas. Three cases of multinodular goiter and one case of Hashimoto's thyroiditis with marked follicular hyperplasia have also been included because they received either a neoplastic or an equivocal cytodiagnosis. Of 22 follicular carcinomas, 12 were diagnosed on FNA as follicular neoplasms, eight as follicular carcinoma, one was a false-negative benign cytodiagnosis, and one was equivocal. Of 11 follicular adenomas, seven were diagnosed as follicular neoplasms and four were cytologically equivocal. Three cases of multinodular goiter and one Hashimoto's thyroiditis had been diagnosed on FNA as either follicular neoplasm or equivocal.     

Dipeptidyl aminopeptidase IV in the cytologic diagnosis of thyroid carcinoma

Recently, the demonstration of DAP IV activity in thyroid cells aspirates has been proposed as an useful tool for the diagnosis of malignancy. We have studied the enzymatic activity of DAP IV, using the modified method of Lodja, in a series of 336 selected aspirates of the thyroid gland with the following cytologic diagnosis: 236 nodular hyperplasias, 60 follicular proliferations, eight Hashimoto's thyroiditis, eight Hürthle-cell proliferations, 20 papillary carcinomas, two anaplastic carcinomas, and two medullary carcinomas. The results were subjectively evaluated on the basis of staining intensity and extension in a minimum of 200 cells. Strong-to-moderate enzymatic activity with an extension of more than 40% of the cells were exclusively seen in follicular-cell derived carcinomas (papillary carcinoma, Hürthle-cell carcinoma, and follicular carcinoma). Medullary carcinoma, anaplastic carcinoma, and benign conditions were negative or weakly stained. Cytohistologic correlation in 88 patients operated on showed the following results: 26 nodular hyperplasia (18 nodular hyperplasia and eight follicular adenomas), 36 follicular proliferation (24 nodular hyperplasia, six, adenomas, three papillary carcinomas, three follicular carcinomas), two Hürthle-cell proliferation (one Hürthle-cell adenoma and one Hürthle-cell carcinoma), 20 papillary carcinomas, two medullary carcinomas, and two anaplastic carcinomas. DAP IV staining was moderate to strong and extensive in all malignant tumors initially diagnosed as follicular or Hürthle-cell proliferations. We conclude that DAP IV activity is present in malignant differentiated thyroid tumors of follicular cells (papillary carcinoma, follicular carcinoma, Hürthle-cell carcinoma), but it is identified neither in medullary carcinoma nor in anaplastic carcinoma. Therefore, its usefulness is restricted to the diagnosis of follicular-cell malignancies. Diagn. Cytopathol. 1998;19:4–8. © 1998 Wiley-Liss, Inc.     

Galectin-3, a marker of well-differentiated thyroid carcinoma, is expressed in thyroid nodules with cytological atypia

AIMS: The distribution of galectin-3, a widely recognized marker of well-differentiated thyroid carcinoma, was investigated in 95 thyroid lesions including nodules with foci of cytoarchitectural atypia. METHODS AND RESULTS: Twenty-eight papillary carcinomas, five follicular carcinomas, one Hurthle cell carcinoma, three poorly differentiated carcinomas, one anaplastic carcinoma, 25 nodular hyperplasias and 27 follicular adenomas, including nodules with atypical features, three neoplasms of undetermined malignant potential and two thyroiditis cases were examined. By immunohistochemistry, galectin-3 was consistently found in carcinomas; otherwise benign nodules exhibited galectin-3-positive clusters of cells with poorly developed features of differentiated carcinoma (mainly of papillary type) such as nuclear chromatin clearing, nuclear clefting, pseudoinclusions, which, in each case, were not histologically sufficient to warrant a definitive diagnosis of malignancy. In other nodules galectin-3 staining was negative. The latter were either clearly benign or showed constantly a minor degree of chromatin clearing and of other atypical features when compared with galectin-3-positive cases. CONCLUSIONS: Galectin-3, a reliable marker of differentiated thyroid carcinoma as confirmed in our series of malignant neoplasms, appears expressed in nodules with an overall benign appearance but with focal areas suspicious for malignancy. The significance of such findings needs to be further investigated.     

Argyrophilic nucleolar organizer regions in colorectal malignancy: application of typing by their density

Colorectal neoplasms obtained at colonoscopy were examined by argyrophilic nucleolar organizer region (AgNOR) staining to evaluate the usefulness of AgNOR as a discriminant for malignancy. AgNOR dots were divided into two kinds: 'structures' (larger and less-densely stained) corresponding to the nucleolus, and 'units' (smaller and densely stained) presumed to be true AgNOR within the structure. The number of structures per nucleus did not differ between the adenoma and carcinoma groups, whereas the number of units per nucleus showed a significant difference. However there were several cases showing an overlap between the adenoma and carcinoma groups, leading to a difficulty in deciding whether any given case was benign or malignant. Three types of AgNOR patterns were categorized based on the ratio of units to structure. Type I was defined as the unit being indistinguishable from the structure, Type II as each structure having one to five units, and Type III as at least one structure having six or more units, irrespective of total number of units per nucleus. The colorectal lesions in which more than half of the neoplastic cells showed Type III coincided well with carcinomas histologically diagnosed, with the exception of adenomas with severe atypia. Labeling index of proliferating cell nuclear antigen (PCNA LI) differed between the adenoma and carcinoma groups with a considerable extent of overlap, and correlated to some extent with the AgNOR values. These results showed that the AgNOR staining was useful for determining malignancy and its usefulness appeared superior to PCNA LI.     

A comparative study of DNA cytometry methods for benign and malignant thyroid tissue

DNA measurements of 46 thyroid specimens were performed by use of fresh tissue for flow cytometry and formalin-fixed paraffin-embedded tissue for flow and static cytometry. The tissue included four histopathologic subgroups, i.e., 19 colloid goiters, 7 papillary carcinomas, 10 follicular adenomas, and 10 follicular carcinomas. The methods measured DNA index and the percentage of cells in S-phase for each subgroup. There was a strong correlation between the methods for DNA-index measurements. In three cases, tissue interpreted as diploid by one method was aneuploid by another method. The S-phase measurements were not reproducible between the methods because of the low percentage of cells in S-phase (mean: 2.6%; range: 0.0-7.5% overall). Aneuploid cells were rare in nodular goiter (2 of 19 cases, 10.5%) but were increasingly present in subsequent subgroups, i.e., 2 of 7 papillary carcinomas (28%), 3 of 10 follicular adenomas (30%), and 6 of 10 follicular carcinomas (60%).