Objective analysis of collagen organization in thyroid nodule capsules using second harmonic generation microscopy images and the Hough transform

Papillary carcinoma is the most prevalent type of thyroid cancer. Its diagnosis requires accurate and subjective analyses from expert pathologists. Here we propose a method based on the Hough transform (HT) to detect and objectively quantify local structural differences in collagen thyroid nodule capsules. Second harmonic generation (SHG) microscopy images were acquired on non-stained histological sections of capsule fragments surrounding the healthy thyroid gland and benign and tumoral/malignant nodules. The HT was applied to each SHG image to extract numerical information on the organization of the collagen architecture in the tissues under analysis. Results show that control thyroid capsule samples present a non-organized structure composed of wavy collagen distribution with local orientations. On the opposite, in capsules surrounding malignant nodules, a remodeling of the collagen network takes place and local undulations disappear, resulting in an aligned pattern with a global preferential orientation. The HT procedure was able to quantitatively differentiate thyroid capsules from capsules surrounding papillary thyroid carcinoma (PTC) nodules. Moreover, the algorithm also reveals that the collagen arrangement of the capsules surrounding benign nodules significantly differs from both the thyroid control and PTC nodule capsules. Combining SHG imaging with the HT results thus in an automatic and objective tool to discriminate between the pathological modifications that affect the capsules of thyroid nodules across the progressions of PTC, with potential to be used in clinical settings to complement current state-of-the-art diagnostic methods.

A Novel Diagnostic Method for Thyroid Follicular Tumors Based on Immunofluorescence Analysis of p53-Binding Protein 1 Expression: Detection of Genomic Instability

Background: The preoperative diagnosis of thyroid follicular carcinomas (FCs) by fine-needle aspiration cytology is almost impossible. It was previously demonstrated that p53-binding protein 1 (53BP1) expression, based on immunofluorescence (IF), can serve as a valuable biomarker to estimate the malignant potential of various cancers. 53BP1 belongs to a class of DNA damage response molecules that rapidly localize to the site of DNA double-strand breaks, forming nuclear foci (NF). This study aimed to elucidate the utility of 53BP1 NF expression as a biomarker to differentiate follicular tumors (FTs). Methods: Associations between 53BP1 expression based on IF and histological types of FTs were analyzed using 27 follicular adenomas (FAs), 28 minimally invasive FCs, and 14 widely invasive FCs. Furthermore, the study clarified the relationship between 53BP1 NF and copy number aberrations (CNAs) based on array comparative genomic hybridization, a hallmark of genomic instability (GIN). Results: This study demonstrates differences in 53BP1 NF expression between FA and FC. The incidence of 53BP1 at NF significantly increased with FT progression in the following order: normal follicle < FA < minimally invasive FCs < widely invasive FCs. In contrast, no significant differences were observed in CNAs among the FT samples. Furthermore, there was no significant correlation between CNAs and 53BP1 at NF in FTs. Thus, based on a comparison of these two indicators of GIN, 53BP1 NF (by IF) was better able to estimate the malignancy of FTs compared to CNA (by array comparative genomic hybridization). Interestingly, IF revealed a heterogenous distribution of 53BP1 NF, which occurred more frequently in the invasive or subcapsular area than in the center of the tumor, suggesting intratumoral heterogeneity of GIN in FTs. Conclusions: It is proposed that IF analysis of 53BP1 expression could be a novel diagnostic method to estimate the malignant potential of FTs. Because 53BP1 NF reflect DNA double-strand breaks, it is hypothesized that the incidence of 53BP1 at NF can represent the level of GIN in tumor cells. IF analysis of 53BP1 expression will not only be an auxiliary histologic technique to diagnose FTs accurately, but also a novel technique for preoperative diagnosis using fine-needle aspiration cytology.

Curious Residents of the Thyroid Gland: Two Case Reports of Colorectal Carcinoma Metastasis by Fine-Needle Aspiration Diagnosis

BACKGROUND

The most frequent metastases to the thyroid originate in the kidney, lung or breast. Colorectal adenocarcinoma represents less than 4% of metastases to the thyroid gland. Solitary metastases of colorectal cancer with no other manifestation of disseminated cancer disease are exceedingly rare. Within the Bethesda Classification for Reporting -Thyroid Cytopathology, metastases are included in Diagnostic Categories "Suspicious for Malignancy" and "Malignant."

CASES

We present 2 cases of colorectal adenocarcinoma metastatic to the thyroid gland, diagnosed by fine-needle aspiration (FNA). One metastasis occurred in normal thyroid parenchyma; the other was a tumour-to-tumour metastasis into a follicular carcinoma of the thyroid. The latter is the first published tumour-to-tumour metastasis of a colorectal carcinoma in the thyroid from which both components were diagnosed by FNA.

CONCLUSION

Diagnosing a metastasis to the thyroid is challenging. On FNA, a dual cell population should raise suspicion. Immunocytochemical and molecular analysis may be helpful. Clinical information is essential in guiding specific ancillary technique panels in scant cellular material.

Incidental thyroid carcinoma in patients with TIR1, TIR2 and TIR3 FNA

AIM

The aim of our study was to evaluate the presence of incidental differentiated thyroid carcinomas, at final histological examination, in patients undergoing thyroidectomy or lobectomy for presumed benign pathology or in those with cytological diagnosis of indeterminate nodules (TIR3).

MATERIAL OF STUDY

457 patients who underwent surgery for benign disease and 179 patients with indeterminate FNA were included in our study.

RESULTS

77 out of 457 patients had the diagnosis of differentiated thyroid carcinoma. 29 out of 179 patients had the same diagnosis as previous ones, but not on the undetermined FNA nodule. In the most of the cases, the istotype was follicular variant of papillary carcinoma.

DISCUSSION

The incidence of incidental carcinomas, approximately the same in the two groups of patients, respectively 16.8% and 16.2%, shows that there is still a group of patients with benign thyroid disease escaping a careful ultrasound evaluation and therefore a targeted FNA. Even in patients with indeterminate cytology, the presence of an incidental carcinoma suggests that on the one hand there has been an overestimation and on the other a non-recognition of the really suspect nodule. Although in most cases it is a microcarcinoma, we must not overlook the presence of many tumors at stage T3.

CONCLUSIONS

Surely the analysis of the set of risk factors with a wider application of molecular biology surveys will in the future lead to better selection of patients to undergo surgery sooner than those that can be followed in follow up even for a longer period of time.

KEY WORDS

Differentiated thyroid carcinoma, Fine needle aspiration, Incidental carcinoma.

E-cadherin/α-catenin deregulated co-expression in thyroid carcinoma based on tissue microarray digital image analysis

PURPOSE

Deregulation of cell-to-cell adhesion molecules is a common and also critical genetic event in epithelial malignancies leading to an increasing metastatic potential. Among them, e-cadherin and catenins--especially α and β--, act as oncogenes during the carcinogenetic process affecting specific signaling transduction pathways (i.e. Wnt/ b-catenin). Concerning thyroid carcinoma, decreased or loss of expression in these proteins seems to affect the biological behavior of the neoplasm increasing its aggressiveness. The aim of this study was to investigate the deregulation of e-cadherin/α-catenin complex in thyroid carcinomas.

METHODS

Thirty-five paraffin-embedded tissue samples including thyroid carcinomas (N=20) and also 15 cases of benign follicular nodules were cored at 1 mm diameter and transferred to a microarray block. Immunohistochemistry (IHC) was performed using anti-e-cadherin/α-catenin antibodies. Digital image analysis was also implemented for measuring the corresponding protein expression levels.

RESULTS

E-cadherin/α-catenin protein expression demonstrated a significant progressive decrease regarding benign and malignant lesions (p=0.001). Simultaneous e-cadherin/α-catenin reduced or loss of expression was observed in 10/20 (50%) cancer cases correlated to advanced stage (especially nodal metastasis) of the examined tumours (p=0.02). Concerning the histological type, combined loss of e-cadherin/α-catenin expression was predominantly associated with follicular and anaplastic histology (p=0.001). Interestingly, α-catenin protein expression pattern was significantly correlated with the grade of differentiation of the examined malignancies (p=0.01).

CONCLUSIONS

Progressive loss of e-cadherin mainly and also α-catenin expression is associated with an aggressive phenotype (low differentiation, increased metastatic activity/advanced stage) in thyroid carcinomas. Based on their aberrant protein expression, novel agents have been developed for restoring their normal function.

Skull metastasis from follicular thyroid carcinoma: report of three cases and review of literature

Three patients' medical history, clinical manifestation, imaging characteristic, therapy and prognosis of calvaria metastasis from follicular thyroid carcinoma (FTC) in our hospital were retrospectively analyzed by reviewing medical literature. In case one, the tumor in frontal bone and fossa orbital was total resected, no further treatment was performed, the patient gave up on therapy and died of extensive metastasis at 22 months after the initial operation. In case two, the tumor in parietal and occipital bone was total resected, the subtotal resection of bilateral thyroid gland and isthmus was performed and combined with therapy of Levothyroxine and (131)I radio-iodine therapy, no evidence of tumor recurrence at 30 months after the primary operation. In case three, the tumor in occipital bone was gross total resected, total resection of bilateral thyroid gland and clearance of lymph node was performed after two months, adjunctive therapy with Levothyroxine, (131)I radio-iodine and skull radiotherapy, no evidence of tumor recurrence at 21 months after the primary operation. Correct diagnosis of calvaria metastasis from FTC preoperative is difficult because it's rarity, patients can survive for years after synthetic therapy including total resection of metastatic tumor, radical operation of thyroid carcinoma, adjunctive therapy of Levothyroxine, (131)I radio-iodine and skull radiotherapy.

Role of GPER1, EGFR and CXCR1 in differentiating between malignant follicular thyroid carcinoma and benign follicular thyroid adenoma

It is extremely difficult to discriminate between follicular thyroid carcinoma (FTC) and follicular thyroid adenoma (FTA) before surgery, because the morphologies of carcinoma cells and adenoma cells obtained by fine needle aspiration biopsy (FNAB) are similar. Molecular markers may be helpful on this issue. The purpose of this study was to assess the role of GPER1, EGFR and CXCR1 in differential diagnosis between FTC and FTA. GPER1, EGFR and CXCR1 mRNA expression levels were examined in 15 FTCs and 10 FTAs using real-time RT-PCR. FTC showed to have significantly increased mRNA levels of the three molecules compared to FTA (P < 0.001 for all the three molecules). GPER1, EGFR and CXCR1 protein expression in 106 FTCs and 128 FTAs were analyzed using immunohistochemistry. The rates of GPER1, EGFR and CXCR1 high expression were 73.6%, 72.6% and 70.8% in FTC and 30.5%, 28.1% and 27.3% in FTA, respectively. Statistical analysis showed that GPER1, EGFR and CXCR1 protein expression were correlated with one another in FTC and concomitant high expression of the three molecules had stronger correlation with the occurrence of FTC than did each alone. The positive predictive values (PPV) for concomitant high expression of the three molecules for discriminating between FTC and FTA were 91.0% for GPER1/EGFR, 93.8% for GPER1/CXCR1, 92.3% for EGFR/CXCR1 and 98.2% for GPER1/EGFR/CXCR1, respectively. These results indicated that the evaluation of GPER1, EGFR and CXCR1 concomitant high expression may be helpful in differential diagnosis between FTC and FTA.

The nightmare of indeterminate follicular proliferations: when liquid-based cytology and ancillary techniques are not a moon landing but a realistic plan

OBJECTIVE

Thyroid nodules are a common finding in the general population, including both nonneoplastic and neoplastic entities. Fine-needle aspiration cytology (FNAC) is the first tool for evaluating thyroid nodules. In spite of its high diagnostic accuracy, 25% of nodules result in the category of follicular neoplasms (FN), with varying risk of malignancy and different management strategies.

STUDY DESIGN

The use of ancillary techniques is reshaping the practice of FNAC. These tools can significantly empower the morphological diagnosis and prognosis of thyroid nodules, allowing a more accurate prediction of the nature of the lesion. Several studies have underlined the role of single or multiple testing for the category of FN as strong indicators of cancer. Every cytological preparation can be used for the application of ancillary techniques but the introduction of liquid-based cytology (LBC) might facilitate the application.

RESULTS

Our experience involving an immunocytochemical panel made up of HBME-1 and galectin-3 pointed to an 81% overall diagnostic accuracy in discriminating between low and high risk of malignancy in FN.

CONCLUSIONS

The application of these techniques on LBC represents an adjunct to the morphological evaluation of FN. They represent a critical and challenging, but also a feasible, tool in the preoperative diagnoses, allowing specific prognostic and predictive details regardless of the cytological preparation. © 2014 S. Karger AG, Basel.

Encapsulated anaplastic thyroid carcinoma transformed from follicular carcinoma: a case report

BACKGROUND

Anaplastic thyroid carcinoma (ATC) is rare but is one of the most aggressive and lethal human malignancies. Cytologically, ATC has a variable morphologic appearance, including squamoid, giant, spindled and pleomorphic cells. The coexistence of ATC and differentiated or poorly differentiated thyroid carcinoma has been described and usually is diagnosed when the disease is locally advanced.

CASE

We describe a case of surgically resectable, encapsulated, well-circumscribed ATC occurring in association with a better differentiated follicular carcinoma diagnosed by fine needle aspiration in a patient exposed to external ionizing radiation.

CONCLUSION

Encapsulated variants of anaplastic carcinoma can be seen in association with lower grade thyroid carcinoma such as follicular carcinoma. Accurate diagnosis is dependent on adequate sampling.

Choroidal metastasis of follicular thyroid adenocarcinoma diagnosed by 25-gauge transretinal biopsy

We report a case of a patient with previously treated follicular thyroid carcinoma who presented with a symptomatic amelanotic choroidal mass with low internal reflectivity and a metastatic lytic skull lesion. A 25-gauge vitrector was used to perform transretinal choroidal biopsy (TRCB), confirming the diagnosis of metastatic follicular thyroid carcinoma.

Distribution of Na+/I- symporter in thyroid cancers in an iodine-deficient population: an immunohistochemical study

BACKGROUND

There are significant differences in the prevalence and behavior of differentiated thyroid cancers (DTC) in the iodine-deficient areas (IDA) and iodine-sufficient areas (ISA) of the world. The sodium iodide symporter (NIS), mediates active transport of iodide across the basolateral aspect of the thyroid follicular cell. However, no study had specifically addressed the issue of expression of sodium iodide symporter (NIS) in thyroid cancer specimens from IDA. The aim of the present study was to find an expression pattern of NIS in DTC in an iodine-deficient population, and to correlate it with histological subtypes, i.e., papillary carcinoma (PTC), follicular carcinoma (FTC), poorly differentiated carcinoma (PDTC), as well as with clinicopathological risk factors and iodine ((131)I) uptake by distant metastases.

METHODS

Immunohistochemistry was carried out in 39 cases of thyroid cancer (41 samples) including PTC (15), FTC (10), PDTC (9), anaplastic cancer (5), and resected metastases (2). Expression was correlated with the patient's age, sex, tumor size, presence or absence of extrathyroidal invasion, distant and lymph node metastases, and whole body radioiodine scan.

RESULTS

Overall, 61.8% of DTC patients showed NIS expression. There was no significant difference in expression rate between PTC (73.3%) and FTC (70.0%). However, expression was significantly less in PDTC (33.3%). There was no correlation between NIS expression and any clinicopathological risk factor (p > .05). The results of NIS expression were not concordant with (131)I uptake by metastases in 4 of 10 cases. (131)I uptake was absent in one case despite the finding that a metastatic site itself showed NIS expression in that case, whereas in the remaining 9 cases (131)I uptake was present although three cases did not show NIS expression.

CONCLUSIONS

In our experience, overall expression of NIS was comparable to other studies from ISA. We conclude that expression may not accurately predict radioactive iodine (RAI) uptake by metastases.

Red lesions of the iris, choroid, and skin secondary to metastatic carcinoma of the thyroid: a review

An 83-year-old man was seen with a history of bilateral progressive loss of vision of 1 month's duration. On examination, there was a reddish, nodular lesion adjacent to the right side of the nose. Slit-lamp examination revealed a reddish iris mass in the left eye. Ophthalmoscopic examination revealed two orange choroidal lesions in the right eye and a large subretinal hemorrhage in the posterior pole with a central reddish vascular lesion in the left eye. An excisional biopsy of the skin lesion was performed. A diagnosis of metastatic follicular thyroid carcinoma was made according to the histopathologic findings and immunohistochemistry. The patient had no known history of thyroid malignancy and a metastatic survey revealed widespread metastasis. The patient had a total thyroidectomy followed by two series of radioactive iodine ablation. The iris lesion completely resolved and the choroidal lesions in the right eye showed partial regression during the follow-up period. Ocular and skin metastasis secondary to thyroid carcinoma is uncommon. In a review of English literature we found reports of 12 clinically well-documented cases of choroidal metastasis and two cases of iris metastasis. Our case and review of the previous cases reveal that reddish/orange color is a commonly observed feature of the uveal metastasis of thyroid carcinoma. Although ocular and skin metastases from thyroid carcinoma are rare, this possibility should be considered in the differential diagnosis of reddish-colored iris and choroidal masses as well as reddish nodular lesions of the scalp, face, and neck.

Extraction of high-integrity RNA suitable for microarray gene expression analysis from long-term stored human thyroid tissues

INTRODUCTION

Isolation of high-quality RNA from fresh-frozen thyroid tissues stored for more than a decade would open novel options for gene expression profiling. Herein, we describe successful extraction of high-integrity RNA from human thyroid tissues that were stored for more than a decade.

METHODS

Seventy-nine samples (15 goitres, 20 follicular adenomas, 30 papillary carcinomas, 14 follicular carcinomas) that were shock-frozen in isopentane and stored for a median of 11 years (range 1-16 years) were processed using standard precipitation and column filtration techniques. RNA integrity was assessed by electrophoresis using the RNA integrity number (RIN) algorithm and by gene expression profiling determining the 3'/5' ratio of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene and the percentage of transcripts detected on the Affymetrix U133 2.0 human genome GeneChip.

RESULTS

The median RNA yield was 1.9 microg/mg tissue (papillary carcinoma 2.1 microg/mg, range 0.2-7.2 microg/mg; follicular carcinoma 2.4 microg/mg, range 0.2-3.2 microg/mg; goitre 1.4 microg/mg, range 0.1-5.4 microg/mg; follicular adenoma 1.6 microg/mg, range 0.1-6.2 microg/mg; p = 0.46) with an 8.6 (7.3-9.8) median RIN. The median GAPDH gene 3'/5' ratio was 1.43 (1.34-1.52) and the median percentage of present calls was 48.1% (42.7-52.0%).

CONCLUSIONS

Age and entity independent RNA suitable for expression profiling can be extracted from long-term stored fresh-frozen human thyroid tissues.

[Preliminary approach towards construction of peptide libraries as potential tools for diagnosis of malignant thyroid tumors]

INTRODUCTION

Cancer of thyroid gland is the most common malignancy of the endocrine system. The treatment improvement could be achieved by early diagnosis. The aim of the study was to identify cancer specific antigenes with use of peptide libraries.

MATERIAL AND METHODS

The material from 6 patients with thyroid cancer (4 with papillary cancer, 1 with follicular cancer and 1 with oxyphilic tumor) were analyzed. It was performed with use of lipophylic peptide libraries by direct comparison of staining of specimens prepared from normal and malignant tissue.

RESULTS

Preliminary results confirm practical value of peptide libraries in early diagnostics of thyroid cancer.

CONCLUSIONS

It is important to optimize construction of peptide libraries by using different staining agents hydrolyzed by proteases.

Expression of matrix metalloproteinases in benign and malignant follicular thyroid lesions

AIMS

To examine expression of matrix metalloproteinases (MMPs) and related proteins in follicular thyroid lesions (FTLs) and to determine their usefulness for differential diagnosis of FTLs, particularly between minimally invasive carcinoma and adenoma.

METHODS AND RESULTS

Six widely invasive follicular carcinomas (WIFCs), 15 minimally invasive follicular carcinomas (MIFCs), 19 follicular adenomas (FAs) and 10 adenomatous goitres (AGs) were analysed immunohistochemically for MMP-1, MMP-2, MMP-7, MMP-9, membrane-type 1-MMP (MT1-MMP) and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2). MMP-1 was positive in all FTLs. MMP-2 and MMP-7 were positive in more than 80% of WIFC and MIFC cases, whereas they were negative in all FA and AG cases except one MMP-2+ FA (P < 0.001). MMP-9 stained positive significantly more in MIFC than FA or AG cases (P < 0.05, respectively). The positivity of MT1-MMP and TIMP-2 was different among some of the FTLs, but with no significant difference between MIFC and FA cases. In-situ hybridization of MMP-2 and MMP-7 mRNA in selected cases demonstrated the expression of these enzymes in the tumour cells as well as in some stromal cells.

CONCLUSIONS

Our results confirm MMP expression mainly in malignant FTLs and suggest that MMP-2 and MMP-7 may be useful markers to distinguish MIFC from FA.

Expression of c-kit, Flk-1, and Flk-2 receptors in benign and malignant tumors of follicular epithelial origin

BACKGROUND

Vascular endothelial growth factor (VEGF) is a key regulator of physiologic as well as pathologic angiogenesis. The response of VEGF to endothelial cell mitogenesis and survival, as well as angiogenesis and microvascular permeability, is mainly mediated through its receptor-2, VEGFR2 (kinase domain receptor or fetal liver kinase-1, KDR or Flk-1). This study aimed to detect the expression of VEGFR2 in various forms of thyroid tumors. In addition, the expression of Flk-2 (receptor for Flt-3) and c-Kit (receptor for steel locus factor), which shows strong similarity to Flk-1, was also examined in thyroid tumors.

METHODS

RT-PCR analyses of c-Kit and immunohistochemical staining of c-Kit, Flk-1, and Flk-2 were performed in archived samples of 18 papillary thyroid carcinoma (PTC), 9 follicular thyroid carcinoma (FTC), 12 follicular adenoma (FA), and 7 nodular goiter (NG) samples. The data were correlated to clinicopathologic features.

RESULTS

By RT-PCR analyses, c-Kit expression was detected in 22% (4/18) of PTC, 22% (2/9) of FTC, 25% (3/12) of FA, and 57% (4/7) of NG samples. However, positive immunostaining signals of c-Kit were only observed in 17% (3/18) of PTC samples, and not in the others. Similarly, Flk-1 expression was only detected by immunohistochemistry in 67% (12/18) of PTC and 43% (3/7) of NG samples, and not in the others. Interestingly, the expression of Flk-2 was found in 89% (16/18) of PTC, 89% (8/9) of FTC, 75% (9/12) of FA, and 29% (2/7) of NG samples. An inverse relationship of thyroid cancer size with Flk-2 expression was found.

CONCLUSION

Flk-2 expression was detected in various forms of thyroid tumors and increased Flk-2 expression was correlated with thyroid tumors with increased transforming activity, suggesting that Flk-2 is involved in pathogenic development of thyroid malignancy. Similarly, Flk-1 expression was also found in some thyroid tumors, while the expression of c-Kit-mediated pathways may not play a major role in thyroid tumorigenesis.

Expression of TAp73 and DeltaNp73 isoform transcripts in thyroid tumours

AIM

This study was aimed to determine p73 status in thyroid tumours.

METHODS

Differential expression of the TAp73, DeltaTAp73 transcripts was measured in a panel of 60 thyroid malignancies by quantitative RT-PCR.

RESULTS

By comparison to normal thyroid tissue surrounding the tumours, we observed significant downregulation of TP73 transcripts in adenomas and in differentiated carcinomas. Correlations were found in normal tissue specimens between the expression of TAp73 and DeltaNp73 transcripts and that of p53, p14ARF p16INK4a, but these correlations were lost in carcinomas (PTC or FTC).

CONCLUSIONS

We have found significant variations of TAp73, DeltaNp73, p53, p14ARF p16INK4a, expressions and correlations between the expressions of those different genes in thyroid cancer.

Thyroid follicular adenocarcinoma in a ferret

A 5-year-old male castrated ferret was presented to the Washington State University College of Veterinary Medicine for evaluation of progressive hair loss and a large, rapidly growing ventral neck mass. The patient had been diagnosed previously with an insulinoma, which was managed medically. Fine-needle aspirates of the neck mass were performed. The cytologic results were most consistent with epithelial neoplasia, likely a carcinoma; thyroid origin was considered likely based on tumor location and cell morphology. The tumor grew rapidly, and the owners elected euthanasia 1 week after examination. At necropsy, a circumscribed, ovoid mass disrupted the right cervical musculature next to the right lobe of the thyroid gland. Histopathologic evaluation revealed an infiltrative mass consisting of cuboidal cells arranged in solid sheets and irregular follicles enclosing colloid. The cells were large, with prominent nucleoli, and had a high mitotic rate. The histopathologic diagnosis was consistent with thyroid follicular adenocarcinoma. Immunochemical findings confirmed thyroglobulin production by neoplastic cells, but to a lesser extent than in normal ferret thyroid tissue. To our knowledge, this is the first case of thyroid follicular adenocarcinoma to be reported in a ferret, with only 1 other case of thyroid carcinoma, a C-cell carcinoma, described previously.

Role of Immunohistochemistry in the Diagnosis and Progression of Follicular Epithelium-Derived Thyroid Carcinoma

Thyroid carcinoma derived from the thyroid hormone-producing follicular epithelium is the most common thyroid malignancy. While the morphologic diagnosis of conventional papillary thyroid carcinoma is simple, thyroid tumors with a follicular pattern are sometimes a diagnostic challenge. It is in the latter group of thyroid neoplasms that ancillary diagnostic tests such as immunohistochemistry may be of great help. Furthermore, while most differentiated thyroid carcinomas have an excellent prognosis, a subset of these tumors may progress to a poorly or undifferentiated phenotype indicating an aggressive biologic behavior that may lead to systemic spread and death. Application of immunohistochemistry to identify a subset of thyroid carcinoma that may progress to a biologically aggressive phenotype may help in the management of patients with thyroid carcinoma. This review discusses the role of immunohistochemistry in the diagnosis and progression of thyroid carcinoma is discussed.

S100A4 Expression Is an Early Event of Papillary Carcinoma of the Thyroid

OBJECTIVES

S100A4 is a calcium-binding protein related to the metastatic potential of carcinoma. In order to elucidate its contribution to the progression of thyroid carcinoma, we investigated S100A4 expression in various thyroid neoplasms.

METHODS

We immunohistochemically examined S100A4 expression in 195 cases of thyroid neoplasms.

RESULTS

Although S100A4 was absent in normal follicular cells and follicular adenoma, S100A4 was positive in all 115 cases of papillary carcinoma examined, including 58 microcarcinomas. However, a significant relationship could not be established between S100A4 expression and clinicopathological features of papillary carcinoma. In follicular carcinoma, the widely invasive type expressed S100A4 more frequently than the minimally invasive type (p = 0.0028). In anaplastic carcinoma, S100A4 was expressed in 61.9% of cases, but the incidence was significantly lower (p < 0.0001) than that in papillary carcinoma.

CONCLUSIONS

These findings suggest that (1) S100A4 plays a constitutive role in papillary carcinoma and (2) S100A4 may be a useful marker for early the detection of this carcinoma.

[Expression of cytokeratin19, galectin-3 and HBME-1 in thyroid lesions and their differential diagnoses]

OBJECTIVE

To study immunohistochemical expression of cytokeratin19 (CK19), galectin-3 (Gal-3) and HBME-1 in thyroid lesions and to assess their usefulness as markers in the differential diagnoses of thyroid nodular lesions.

METHODS

Immunohistochemical staining was performed on formalin-fixed paraffin-embedded tissue of 21 cases of nodular goiters, 14 cases of toxic goiters, 15 cases of follicular adenomas (FA), 13 cases of follicular carcinomas (FC), 13 cases of follicular variant papillary carcinomas (FVPC) and 48 cases of classic papillary carcinomas (CPC).

RESULTS

All three markers were expressed in the cytoplasm with no or weak expression in benign lesions and diffuse and strong in malignant cases. Positive expressions of CK19, Gal-3 and HBME-1 were present in 11of 21, two of 21, four of 21 in nodular goiters, seven of 14, one of 14, one of 14 in toxic goiters, nine of 15, two of 15, two of 15 in FA, 10 of 13, eight of 13, seven of 13 in FC, 13 of 13, 11 of 13, 12 of 13 in FVPC, and 48 of 48, 45 of 48, 46 of 48 in CPC. The expression rates of the three markers between benign lesions (nodular goiters, toxic goiters and FA) and malignant lesions (FA, FVPC and CPC) were statistically significant. Among the three follicular lesions (FA, FC and FVPC), the differences were statistically significant as well. Nine, seven and six cases were negative for all three markers in nodular goiters, toxic goiters and FA, respectively. Only one case in FC was negative for all three markers, no case was all negative in FVPC and CPC; the rate of one case with two or more positive marker expression in nodular goiters, toxic goiters, FA, FC, FVPC and PC was 14.2% (3/21), 21.43% (3/14), 20.0% (3/15), 69.2% (9/13), 92.3% (12/13), 100.0% (48/48), the differences between benign lesions and malignant lesions and between FA, FC and FVPC were also statistically significant.

CONCLUSIONS

Immunohistochemical stains of CK19, Gal-3 and HBME-1, especially when used in combination, can be an important adjunct to the histopathological diagnoses of thyroid lesions.

Galectin-3: presurgical marker of thyroid follicular epithelial cell-derived carcinomas

Preoperative follicular lesion characterisation represents an unsolved diagnostic problem in thyroid nodular disease. Although fine-needle aspiration biopsy is the most reliable preoperative diagnostic procedure, it shows inherent limitations in differentiating adenoma from follicular carcinoma and, sometimes, follicular variants of papillary carcinoma. Galectin-3 cytoplasmic neoexpression has been proposed as a peculiar feature of thyroid malignant cells, easily detectable in cytological and histological samples. The aim of this study was to re-evaluate the galectin-3 expression in a large sample of thyroid lesions using an immunohistocytochemical biotin-free detection system and a specific anti-human-galectin-3 monoclonal antibody in order to avoid the interference of technical factors, a cause of conflicting results recently reported by some authors. We analysed galectin-3 expression of 39 follicular carcinomas, 26 papillary carcinomas, and 105 adenomas in both cell-block samples and their histological counterparts. All cell-block and histological papillary carcinoma samples showed high levels of galectin-3 immunoreactivity. Thirty-four follicular carcinomas were positive, whereas 5 were negative in cell-blocks but positive in their histological counterparts. Twelve out of 105 adenomas expressed galectin-3 in cell-blocks and histological samples. The diagnostic accuracy of preoperative galectin-3 evaluation in adenomas vs follicular carcinomas was 90.0%. Galectin-3 expression was also investigated in 22 minimally-invasive follicular carcinomas. All of them showed galectin-3 immunoreactivity in both cytological and histological specimens with the exception of two cases, where galectin-3 positivity was observed only in the surgical material. The routine correct use of galectin-3, by increasing the diagnostic accuracy of conventional cytology, improves the management of thyroid nodules and can lead to a sensitive reduction of useless thyroid surgeries.

HBME-1 y ciclina D1: marcadores diagnósticos de carcinoma folicular del tiroides

BACKGROUND

Follicular carcinomas account for 15% of thyroid malignant tumors. The differential diagnosis between adenoma and minimally invasive follicular carcinoma is difficult and lacks reproducibility especially in frozen sections. As the diagnosis depends on finding foci of capsular invasion, multiple sections must be examined. Numerous immunohistochemical markers have been studied for determining malignancy.

AIM

To assess the efficacy of HBME-1 and Cyclin-D1 as diagnostic markers for follicular thyroid carcinoma.

MATERIAL AND METHOD

We evaluated retrospectively 21 thyroidectomy specimens of 18 women and 3 men with diagnosis of adenoma or follicular carcinomas, both by hematoxylin and eosin stain and by immunohistochemistry using the avidin biotin method for the markers HBME-1 and Cyclin D1.

RESULTS

The sensitivity and specificity of HBME-1 for the diagnosis of follicular thyroid carcinoma, were 88.9% and 100%, respectively whereas for Cyclin D1 the sensitivity and specificity were 22.2% and 100%, respectively. There were no false positive cases.

CONCLUSIONS

HBME-1 has excellent sensitivity and specificity for the diagnosis of follicular carcinoma.

The influence of the vascularisation of the follicular thyroid nodules on the proliferative activity of the follicular cells

The enlargement of the thyroid is, in general, benign in origin and due to nodular goitre. Follicular cellular proliferation of thyroid nodules has been increasingly observed recently. With fine needle aspiration biopsy (FNAB) this is classified as a follicular tumour. These lesions present various patterns of vascularisation in ultrasound examination. The aim of the study was to establish the relation between follicular nodule vascularisation and the proliferative activity of various types of follicular cell. According to the manner of proliferation, patients were divided into groups as follows: (I). patients with hyperplastic nodules (46 cases), (II). patients with follicular adenoma (42 cases), and (III). patients with follicular cancer (9 cases). In each case B-mode sonography, Power Doppler, sonographically guided FNAB (S-FNAB), morphological examination and morphometry were performed. The proliferative activity was detected with immunohistochemical methods (PCNA, Ki 67 and MPM2) to determine the so-called "proliferative index". The study revealed increased proliferative activity in tumours of malignant origin and increased vascularisation in coexistence with increased proliferation of the follicular cells. As assessed by Power Doppler, an increased flow pattern in the centre of the nodules correlates with increased proliferative activity. The results suggest that Power Doppler examination could be helpful in selecting nodules for FNAB, especially in multinodular goitre.

Peroxisome proliferator-activated receptor gamma expression in follicular-patterned thyroid lesions. Caveats for the use of immunohistochemical studies

To determine its usefulness as a specific diagnostic marker for follicular carcinomas (FCs) vs other follicular-patterned thyroid lesions and possible application to fine-needle aspiration specimens, we immunohistochemically studied peroxisome proliferator-activated receptor gamma (PPAR gamma) expression in histologic sections (FC, 13 cases; follicular adenoma [FA], 11; follicular variant of papillary carcinoma [FVPC], 9) and surrounding thyroid tissue by using a PPAR gamma monoclonal antibody. Positivity (detected by nuclear staining) was scored as absent, weak, moderate, or strong. When only moderate or strong nuclear staining was considered positive, 9 FCs (69%), 3 FAs (27%), and 2 FVPCs (22%) demonstrated positive nuclear immunoreactivity. The sensitivity and specificity of immunohistochemical detection of PPAR gamma expression in FCs were 69% and 75%, respectively. In nonlesional surrounding tissue, moderate to strong positive staining was seen in focal areas of chronic lymphocytic thyroiditis in 6 of 33 cases (FC, 2; FA, 3; FVPC, 1); diffuse moderate staining was detected in surrounding tissue in the absence of lymphocytic thyroiditis in 4 cases (12%; FC, 3; FA, 1). Staining in the follicular-patterned lesions and surrounding nonlesional thyroid was specific with peptide blocking experiments. PPAR gamma expression is not a specific marker for FCs, and its detection in nonlesional thyroid tissue suggests limited usefulness as a diagnostic marker for follicular-patterned lesions in general.

Co-expression of interleukin-6 (IL-6) and interleukin-6 receptor (IL-6R) in thyroid nodules is associated with co-expression of CD30 ligand/CD30 receptor

Data on the expression of interleukin 6 (IL-6)/interleukin 6 receptor (IL-6R) in thyroid nodules is scarce. Based on our recent data of CD30 ligand (CD30L)/CD30 receptor (CD30) in these nodules and on the knowledge that this signal stimulates IL-6 production in non-thyroid neoplasms, we wanted to evaluate the immunocytochemical expression of these 2 ligand/receptor systems in a large archival series of paraffin-embedded specimens. These specimens included 6 normal thyroids and 130 thyroid nodules. Co-expression of IL-6 and IL-6R in the epithelial (follicular) cells was observed solely in CD30L/CD30 positive nodules: 5/15 (33%) oncocytic adenomas; 6/30 (20%) follicular adenomas which belonged to 2 variants (4/4 microfollicular toxic and 2/2 hyalinizing trabecular); 9/30 (30%) papillary thyroid cancers (PTC), all belonging to the conventional variant. In PTC the proportion of tumor epithelial cells that were IL6 positive was inversely correlated with the pTNM staging (r=-0.549, p=0.01). All 15 follicular cancers (FTC), all 6 anaplastic cancers (ATC) were IL-6/lL-6R negative; 14/15 FTC and 5/6 ATC were CD30L/CD30 negative. In another oncocytic adenoma, another 4 conventional PTC and another 7 non-conventional PTC CD30L/CD30 expression was associated to expression of IL-6 only. IL-6 staining associated to absent expression of CD30L and CD30 was observed in 7 follicular adenomas (all belonging to variants different from toxic and hyalinizing trabecular), 2 oncocytic adenomas, 5 of the 30 colloid nodules and 2 normal thyroids. Of the 6 tumors arising from the parafollicular C cells (medullary thyroid cancer, MTC), all 3 that had metastasized were CD30L/CD30/IL-6 positive and IL-6R negative; only IL-6 expression was lost in both the local and distant metastases. This finding matched the loss of IL-6 expression in one PTC metastasis. All 3 non-metastasized MTC were IL-6/IL-6R negative, and 1/3 was CD30L positive/CD30 negative. We conclude that only in a subset of both benign and malignant thyroid nodules the IL-6/IL-6R signal could be induced by the CD30L/CD30. IL-6 expression is related with aggressiveness in both PTC and MTC. In the normal thyroid tissue, colloid nodules, and another subset of benign and malignant thyroid nodules, IL-6 expression is under control of signals other than CD30L/CD30.

High molecular weight caldesmon positive stromal cells in the capsule of thyroid follicular tumours and tumour-like lesions

AIMS

To investigate the smooth muscle nature of the spindle stromal cells in the capsule of thyroid tumours and tumour-like lesions.

METHODS

Immunostaining for high molecular weight caldesmon (HCD), a highly specific marker for smooth muscle differentiation, was performed in 70 primary thyroid tumours and tumour-like lesions (21 hyperplastic nodules, 29 follicular adenomas, five minimally invasive follicular carcinomas, six widely invasive follicular carcinomas, and nine encapsulated papillary carcinomas).

RESULTS

HCD positive stromal cells (HCD+ cells) were detected in the capsule of 20 of the 21 hyperplastic nodules, and all of the 29 follicular adenomas and five minimally invasive follicular carcinomas, whereas HCD+ cells were seen in the capsule of only four of the six widely invasive follicular carcinomas and no HCD+ cells were seen in the capsule of the nine encapsulated papillary carcinomas examined.

CONCLUSIONS

The presence of HCD+ cells in the capsule is characteristic of thyroid follicular tumours and tumour-like lesions. The stromal cells in the capsule of thyroid follicular tumours and tumour-like lesions are different from those of encapsulated papillary carcinoma.

Differentiated thyroid carcinoma that express sodium-iodide symporter have a lower risk of recurrence for children and adolescents

The sodium-iodide symporter (NIS) is expressed by papillary (PTC) and follicular (FTC) thyroid carcinoma, and is essential for iodine uptake. We hypothesized that PTC and FTC with detectable NIS immunostaining would be more amenable to radioactive iodine ((131)I) treatment and follow a more benevolent course. To test this, we determined NIS expression by immunohistochemistry in 23 PTC, 9 FTC, and 12 benign thyroid lesions from children and adolescents. NIS expression was determined by two blinded examiners and graded as absent = 0, minimal = 1, moderate = 2, intense = 3, and very intense = 4. NIS was detected in 35% (eight of 23) of PTC, 44% (four of 9) of FTC, 25% (two of eight) of benign tumors, and 100% (four of four) of autoimmune lesions. The intensity of NIS expression was similar in PTC (0.61 +/- 0.24), FTC (0.56 +/- 0.24), and benign tumors (0.50 +/- 0.33) but was more intense in autoimmune lesions (3.0 +/- 0.7, p < 0.005). Distant metastases were found only among PTC with undetectable NIS (two of 15, 13%), and recurrence developed exclusively from PTC and FTC with undetectable NIS (four of 20, 20% versus zero of 12, p = 0.043). The dose of iodine 131 required to achieve remission in the five patients with PTC who had undetectable NIS (213.3 +/- 53 mCi) was greater than that required by patients with similar age and extent of disease for whom NIS expression is unknown (109 +/- 22 mCi, p = 0.06). We conclude that NIS expression is associated with a lower risk of recurrence for PTC and FTC of children and adolescents.

Galectin-3 messenger ribonucleic acid and protein are expressed in benign thyroid tumors

Galectin-3 is a protein of the lectin family that has been associated with neoplastic processes in various tissues. In the thyroid, expression of this protein has been described in differentiated follicular cancer, suggesting that the immunohistochemical study of galectin-3 may be a potential marker of malignancy in thyroid neoplasms. The confirmation of these results may represent an extremely useful tool for presurgical diagnosis and medical conduct. In this study, galectin-3 protein and mRNA expression were analyzed in the thyroid tissues from 87 patients with histomorphological diagnosis of multinodular goiter (MNG) (n = 24), follicular adenoma (n = 31), follicular carcinoma (n = 20), papillary carcinoma (n = 12), and five normal tissues. Galectin-3 protein expression was detected by immunohistochemical method in light, fluorescence, and confocal microscopy, using monoclonal antibody. Galectin-3 mRNA expression was detected by the RT-PCR method. Our results showed that the majority of carcinomas expressed galectin-3 protein (follicular, 90%; papillary, 100%). However, in contrast to the previously published data, benign lesions also expressed galectin-3 (adenoma, 45%; MNG, 17%). We further demonstrated by RT-PCR that thyroid tissues with diagnosis of adenoma and MNG-expressed galectin-3 mRNA. Although the galectin-3 immunostaining demonstrated a sensitivity of 93.8% in the identification of cancer, the accuracy in the distinction between benign and malignant tissues was 77.0%. This accuracy was even lower (68.6%) when the galectin-3 expression in follicular adenoma was compared with follicular carcinoma. Thus, the use of galectin-3 immunodetection as a molecular marker for thyroid carcinoma must be interpreted with caution, particularly in the differentiation between thyroid follicular carcinoma and follicular adenoma.

Determination of galectin-3 messenger ribonucleic Acid overexpression in papillary thyroid cancer by quantitative reverse transcription-polymerase chain reaction

Galectin-3, a lectin-family protein that appears to be involved in malignant transformation, has been reported to be an accurate immunohistochemical marker for thyroid cancer. However, immunohistochemistry is a subjective method that can be difficult to apply to cytologic specimens. Therefore, we sought to develop an objective and quantitative assay to measure galectin-3 mRNA in thyroid tissue to enhance potential clinical use of galectin-3 in the molecular analysis of thyroid nodules. In this study, total RNA from 37 snap-frozen thyroid tissue specimens was isolated from eight papillary and nine follicular thyroid cancers, six follicular adenomas, seven adenomatoid nodules, and seven normal thyroid lobes from patients undergoing thyroidectomy. Normalized levels of galectin-3 mRNA, expressed as picograms per nanogram GAPDH mRNA, were higher in papillary carcinomas (3327 pg/ng) and follicular adenomas (1314 pg/ng) than in thyroid normal tissue (426 pg/ng; P = 0.0012 and 0.032, respectively). Galectin-3 mRNA levels were also higher in papillary cancers than in adenomatoid nodules (P = 0.0012). However, galectin-3 mRNA levels were not statistically greater in follicular carcinomas than either normal tissue or follicular adenomas (P = 0.068 and 0.12, respectively). In summary, in comparison to galectin-3 immunohistochemistry, quantitative measurement of galectin-3 mRNA appears useful in the identification of papillary thyroid cancers (PTCs) but does not appear to be useful in distinguishing follicular carcinomas from follicular adenomas.

Nitrotyrosine, inducible nitric oxide synthase (iNOS), and endothelial nitric oxide synthase (eNOS) are increased in thyroid tumors from children and adolescents

Nitric oxide (NO) is a reactive cell signal that controls vascular tone and is generated by inducible (iNOS), endothelial (eNOS) and neuronal (nNOS) NO synthase (NOS). We hypothesized that NO could be important for growth of thyroid tumors and tested this hypothesis, by staining 41 papillary thyroid carcinoma (PTC), 9 follicular thyroid carcinoma (FTC), and 15 benign thyroid lesions for iNOS, eNOS and nitrotyrosine (N-TYR). Staining intensity was determined by 2 blinded, independent examiners, and quantified from grade 1 (absent) to grade 4 (intense). Average N-TYR staining of benign adenomas (2.5+/-0.42, p=0.009), PTC (3.10+/-0.12, p=0.001), FTC (2.44+/-0.30, p=0.001), and autoimmune lesions (3.25+/-0.48, p=0.019) were greater than that of multinodular goiter (1.0 for all 3) and surrounding normal thyroid (1.1+/-0.1). Average iNOS staining of benign adenomas (2.6+/-0.37), PTC (2.7+/-0.16), FTC (2.4+/-0.26) and autoimmune lesions (3.5+/-0.29) were all greater than that of surrounding normal thyroid (1.1+/-0.1, p<0.008), but there were too few multinodular goiters to achieve a significant difference (no.=2, 3.0+/-1.0). Average eNOS staining of benign adenomas (2.9+/-0.40), multinodular goiters (3.5+/-0.5), PTC (3.24+/-0.18), FTC (3.5+/-0.50), and autoimmune lesions (2.8+/-0.6) were also greater than that of surrounding normal thyroid (mean=1.4+/-0.2, p<0.001). N-TYR staining correlated with that of vascular endothelial growth factor (VEGF, r=0.36, p=0.007) and the number of lymphocytes/high power field (r=0.39, p=0.004). Recurrent disease developed only from carcinoma with moderate-intense N-TYR staining, but there were too few recurrent tumors to achieve statistical significance (p=0.08). We conclude that NO is produced by benign adenomas, PTC and FTC suggesting that NO could be important in vascularization of thyroid tumors and autoimmune thyroid diseases.

Interpretation of RET immunostaining in follicular lesions of the thyroid

We applied monoclonal antibodies against RET and cytokeratin 19 (CK19) to the following tumor sections: classic papillary carcinoma (PC), 16; Hürthle-type PC (HPC), 1; sclerosing PC with nodular fasciitis-like stroma (SPC), 1; PC, follicular variant (FVPC), 12; follicular adenoma (FA), 9; Hürthle cell adenoma (HA), 4; Hürthle cell carcinoma (HC), 3; and follicular carcinoma (FC), 7. CK19+ tumors included 16 PCs, 1HPC, 1SPC, 11 FVPCs, 7 FAs, 4 FCs, and 1HC. RET+ tumors included 4 HAs, 3 HCs, 1HPC, 12 PCs, 7 FVPCs, and 2 FAs. Reverse transcriptase-polymerase chain reaction (RT-PCR) revealed a RET transcript in 6 Hürthle cell lesions. RET immunoreactivity is less sensitive and specific for PC than CK19. CK19 is useful for identifying PC, although only lesions with diffuse, intense staining should be considered positive. The detection of RET protein by immunohistochemical analysis was corroborated by the presence of the RET transcript by RT-PCR. Further study is warranted to determine whether this represents activation by gene fusion or some other mechanism in this subset of thyroid neoplasms.

Ki-67 and AgNOR proliferative markers as diagnostic adjuncts to fine needle aspiration cytology of thyroid follicular lesions

OBJECTIVE

To differentiate hyperplastic nodules (HPN), follicular adenoma (FA) and follicular carcinoma (FCA) of the thyroid by cytomorphologic features combined with argyrophilic nucleolar organizer regions (AgNORs) and Ki-67 proliferative markers on fine needle aspiration cytology.

STUDY DESIGN

Cytomorphologic patterns, along with two proliferation markers, Ki-67 and AgNORs, in fine needle aspirates of 123 histologically confirmed cases of thyroid follicular lesions, including 39 hyperplastic nodules, 70 follicular adenomas and 14 cases of follicular carcinomas, were recorded.

RESULTS

Mean AgNOR (mAgNOR) counts and Ki-67 labelling index (LI) were consistently higher in FCA in comparison to FA and HPN irrespective of the cytologic patterns in fine needle aspiration smears. Between benign and malignant lesions, an overlap of 1.83% at the cutoff point of 4.0 was observed in cases of mAgNORs, whereas it was 11.09% at a cutoff of 5.0 in cases of Ki-67 LI.

CONCLUSION

mAgNOR counting in fine needle aspiration smears is more sensitive, simple and cost effective as compared to Ki-67 LI for differentiating between benign and malignant thyroid follicular neoplasms.

[Update on differenciated thyroid carcinoma]

Differenciated thyroid carcinomas are the most frequently encountered endocrine tumours. These hormono-dependent carcinomas have a good prognosis. Data derived from molecular biology allowed a better understanding of pathophysiological mechanisms involved in tumorigenesis of thyroid papillar and follicular carcinomas. The use of the works derived from molecular biology also allowed a better diagnostic and therapeutic management of the thyroid cancer patients, particularly using recombinant human TSH. Familial thyroid cancer disease must also be recognised to optimise the clinical managemet of patients and their family.

Follicular, papillary, and "hybrid" carcinomas of the thyroid

The existence of well-differentiated thyroid tumors sharing the clinicopathologic features of follicular and papillary carcinoma is discussed using the so-called diffuse (multinodular) form of the follicular variant of papillary carcinoma as a paradigm. Although the concept of a hybrid carcinoma of the thyroid is intellectually very appealing, we conclude that there is not (yet) enough reliable genotypic or phenotypic evidence to support utilization of such a term.

3-D analysis of vascular and capsular invasion in thyroid follicular carcinoma

To clarify the mechanism of vascular invasion (VI) and capsular invasion (CI) in thyroid follicular carcinoma (FC), 3-D reconstruction of tumor tissues, vessels and capsules was performed from serial sections in five FC and three follicular adenomas (FA). Outflow veins in the lesions were well developed under the capsule, narrowed just beneath the capsule, and dilated within the capsule. Both VI and CI were observed at the poststenotic intracapsular dilated part of outflow veins. The tumor tissue extended along the intracapsular horizontal veins which flowed in parallel with the capsule in VI, or along the vertical veins which directly flowed outside the capsule in CI. There was tumor tissue in the subendothelial layer of the outflow veins within the capsule. Intravascular tumor nests and nodular lesions within the capsule continued from the main tumors. It can be concluded from these results that most VI and CI may not be true invasions but pre-invasive lesions.

Immunohistochemical diagnosis of papillary thyroid carcinoma

In thyroid, the diagnosis of papillary carcinoma (PC) is based on nuclear features; however, identification of these features is inconsistent and controversial. Proposed markers of PC include HBME-1, specific cytokeratins (CK) such as CK19, and ret, the latter reflecting a ret/PTC rearrangement. We applied immunohistochemical stains to determine the diagnostic accuracy of these three markers. Formalin-fixed, paraffin-embedded tissue from 232 surgically resected thyroid nodules included 40 hyperplastic nodules (NH), 35 follicular adenomas (FA), 138 papillary carcinomas (PC; 54 classical papillary tumors and 84 follicular variant papillary carcinomas [FVPC]), 4 follicular carcinomas (FC), 6 insular carcinomas (IC), 7 Hürthle cell carcinomas (HCC), and 2 anaplastic carcinomas (AC). HBME-1 and ret were negative in all NH and FA; some of these exhibited focal CK19 reactivity in areas of degeneration. Half of the FC and AC exhibited HBME-1 staining but no positivity for CK19 or ret. In PC, 20% of cases stained for all three markers. Classical PC had the highest positivity with staining for HBME-1 in 70%, CK19 in 80%, and ret in 78%. FVPC were positive for HBME-1 in 45%, for CK19 in 57%, and for ret in 63%; only 7 FVPC were negative for all three markers. The six IC exhibited 67% staining for HBME-1 and 50% positivity for CK19 and ret. The seven HCC had 29% positivity for HBME-1 and CK19, and 57% positivity for ret. This panel of three immunohistochemical markers provides a useful means of diagnosing PC. Focal CK19 staining may be found in benign lesions, but diffuse positivity is characteristic of PC. HBME-1 positivity indicates malignancy but not papillary differentiation. Only rarely are all three markers negative in PC; this panel therefore provides an objective and reproducible tool for the analysis of difficult thyroid nodules.

Poorly differentiated follicular thyroid carcinoma with rhabdoid phenotype: a clinicopathologic, immunohistochemical and electron microscopic study of two cases

Poorly differentiated thyroid carcinomas with follicular cell phenotype are not well defined. Different diagnostic criteria have been employed for these tumors, including solid growth, nodular, trabecular, and insular patterns. Cytologic features, such as a predominance of tall and columnar cells, have been considered to be diagnostic of poorly differentiated carcinoma. However, there is no agreement among surgical pathologists regarding morphologic criteria for poorly differentiated thyroid carcinoma. We report two unique thyroid neoplasms that we interpreted as poorly differentiated follicular carcinomas. Nodular, trabecular, and sheetlike patterns predominated in both tumors. They were composed of cells that were focally immunoreactive for thyroglobulin and had large vesicular nuclei with prominent nucleoli. A variable number of cells showed rhabdoid phenotype. The rhabdoid inclusions did not stain for thyroglobulin but contained whorls of intermediate filaments that were vimentin positive. There were foci of necrosis and numerous mitotic figures. Both patients were adults and died with multiple pulmonary metastases. The presence of rhabdoid cells in poorly differentiated follicular carcinomas broadens the spectrum of tumors with rhabdoid phenotype. More cases are needed to determine whether the rhabdoid phenotype is a marker for poorly differentiated follicular carcinoma as well as an independent adverse prognostic factor.

[HBME-1 immunostaining in thyroid pathology]

The aim of this study was to evaluate wether HBME-1 immunohistochemical analysis can reliably differentiate benign thyroid lesions from thyroid carcinomas. Fifty benign and 87 malignant lesions were analyzed. All papillary carcinomas (67/67) were HBME-1 positive, as well as 14 of 20 follicular well-differentiated carcinomas and 13 of 29 atypical follicular adenomas and 4 out of 21 goiters were weakly and focally positive. HBME-1 highlighted micronests of papillary carcinomas. The reactivity of HBME-1 in the tall-cell variant of papillary carcinomas was apical and stronger than in classical papillary carcinomas. Positive HBME-1 immunostaining is in support of the diagnosis of the follicular variant of papillary carcinoma and highlights micropapillary carcinomas. HBME-1 may be of additional value in the diagnosis of thyroid malignancy.

Activin A and activin receptors in thyroid cancer

Proliferation is controlled by a network of mitogenic and growth inhibitory factors. Transforming growth factor-beta1 (TGF-beta1) and activin A are the most important growth inhibitors of benign follicular epithelial cells of the human thyroid. The effects of these substances on malignant primary thyrocytes are not known. We have examined the growth regulatory effects of activin A and TGF-beta1 in primary cultures derived from four papillary cancers, two follicular thyroid cancers, and three benign thyroid tissues. Malignant cells demonstrated resistance to activin and TGF-beta1 or reversal to a weak but significant mitogenic effect (p < 0.001). We also evaluated the activin receptor transcription pattern. Isoforms alk4-1, 4-2, and 4-3 were found in benign (n = 12) and malignant (n = 22) tissues. Two subtypes of type I and type II activin receptors were demonstrated. Semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) demonstrated a significant threefold downregulation of alk4-1 receptors in papillary (n = 25) and follicular (n = 18) thyroid cancers as compared to normal thyroids (n = 12) (p < 0.001). To our knowledge these are the first data to demonstrate reversal of activin and TGF-beta1 effects in thyroid malignancy and to demonstrate changes of the type Ib activin receptor expression in thyroid malignancy.

Follicular carcinoma of the thyroid with extensive clear-cell differentiation: a potential diagnostic pitfall

Clear-cell features have been recognized in several different thyroid neoplasms. A case of thyroid follicular carcinoma with extensive clear- and Hurthle-cell features is described in a 37-yr-old white female, with cytochemical and immunohistochemical analysis. The tumor of the thyroid gland, with anterior neck soft-tissue extension, displayed clear cells on fine-needle aspiration, which were negative for thyroglobulin. The surgical specimen displayed predominately clear cells (80%), and only the nonclear-cell areas stained for thyroglobulin. Proper categorization of clear-cell lesions of the thyroid and soft tissues requires a multimodality approach, involving clinical/pathological correlation, morphological analysis, and ancillary tissue studies. Immunohistochemical stains for thyroglobulin are quite definitive in making the distinction between primary clear-cell thyroid tumors vs. metastatic clear-cell tumors. Cytologists should be aware, however, that the clear-cell areas of thyroid tumors might not stain for thyroglobulin.

MIB-1 immunohistometry of follicular adenoma and follicular carcinoma of the thyroid gland

OBJECTIVE

To analyze cellular proliferative activity, MIB-1 immunopositivity of normal tissue (n = 20), follicular adenoma (n = 30) and follicular carcinoma (n = 32) of the thyroid gland was analyzed by means of immunohistometry.

STUDY DESIGN

Immunohistochemical reactions were performed on 3-micron sections from routinely formalin fixed and paraffin embedded surgical specimens using an indirect peroxidase method. The rate of immunostained cells was determined using the CM-2 TV image analysis system (Hund, Wetzlar, Federal Republic of Germany). Forty viewing fields (1.94 mm2) were measured with 20:1 objective magnification. An average of 5,965 cells were assessed in each case.

RESULTS

Mean MIB-1 immunopositivity was higher in follicular carcinoma (average, 2.30%) and follicular adenoma (0.58%) than in normal thyroid tissue (0.14%). The distribution of single values differed significantly between groups (P < .001). To test the suitability of MIB-1 immunohistometry for the differential diagnosis of follicular adenoma and follicular carcinoma, different four-field tables with varying thresholds were calculated. Using a threshold of 0.9%, follicular carcinoma could be detected with a sensitivity of 75% (24/32) and a specificity of 83% (25/30). If a specificity of 90% is required (27/30), the sensitivity of the test decreases to 69% (22/32), based on a threshold of 1.1%.

CONCLUSION

As some overlap of single values has to be considered, MIB-1 immunohistometry, although presenting new insights into the proliferative potential of thyroid lesions, is of only limited value for the differential diagnosis of follicular lesions in routine surgical pathology.

Follicular carcinoma of the thyroid with extensive clear-cell differentiation: a potential diagnostic pitfall

Clear-cell features have been recognized in several different thyroid neoplasms. A case of thyroid follicular carcinoma with extensive clear- and Hurthle-cell features is described in a 37-yr-old white female, with cytochemical and immunohistochemical analysis. The tumor of the thyroid gland, with anterior neck soft-tissue extension, displayed clear cells on fine-needle aspiration, which were negative for thyroglobulin. The surgical specimen displayed predominately clear cells (80%), and only the nonclear-cell areas stained for thyroblobulin. Proper categorization of clear-cell lesions of the thyroid and soft tissues requires a multimodality approach, involving clinical/pathological correlation, morphological analysis, and ancillary tissue studies. Immunohistochemical stains for thyroglobulin are quite definitive in making the distinction between primary clear-cell thyroid tumors vs. metastatic clear-cell tumors. Cytologists should be aware, however, that the clear-cell areas of thyroid tumors might not stain for thyroglobulin.

Expression of Pax-8, p53 and bcl-2 in human benign and malignant thyroid diseases

BACKGROUND

Immunohistochemical expression of the transcription factor Pax-8 in human thyroid diseases has never been investigated. The relationship between Pax-8, bcl-2 and p53 in thyroid neoplasms is also matter of interest.

MATERIALS AND METHODS

Seventy-three thyroid tissue samples were evaluated for the expression of Pax-8, p53 and bcl-2 using the immunoperoxidase technique. The series included 11 follicular adenomas, 11 goitres, 23 papillary carcinomas, 16 follicular carcinomas, 6 undifferentiated carcinomas and 6 medullary carcinomas.

RESULTS

The percentage of Pax-8 positive cells ranged from 14.9 to 27.1% and 10.1 to 39% in goitres and follicular adenomas, respectively. Among differentiated carcinomas, follicular histotype showed a Pax-8 immunoreactivity ranging from 0 to 26.5% of the neoplastic cells whereas in papillary carcinomas the percentage of positive cells ranged from 0 to 16.8%. None out of the six undifferentiated carcinomas showed Pax-8 immunoreactivity. The same negative pattern was noticed in medullary carcinomas. A statistically significant difference in Pax-8 expression was observed between non-malignant and malignant diseases (p < 0.0001). A different reactivity for Pax-8 was also noticed between differentiated carcinomas and undifferentiated carcinomas (p = 0.07). None of the benign tissues stained for p53 whereas among malignant specimens different percentages of p53 expression were observed with all undifferentiated carcinomas expressing the highest positivity (range 24.1-88.6%). Finally, when a combined analysis of bcl-2 and Pax-8 reactivity was carried out, some carcinomas proved to be Pax-8 negative and bcl-2 positive whereas others showed a similar immunoreactive pattern for both Pax-8 and bcl-2.

CONCLUSIONS

Pax-8 is mainly expressed in benign rather than in malignant thyroid diseases and, among neoplasms, differentiated carcinomas express Pax-8 more frequently than undifferentiated carcinomas. An inverse pattern was observed for p53. Bcl-2 seems to be partially related to Pax-8 expression. However, a Pax-8 independent bcl-2 expression is also evident.

Expression of cytokeratin 20 in thyroid carcinomas and peripheral blood detected by reverse transcription polymerase chain reaction

We investigated a nested reverse transcriptase polymerase chain reaction (RT-PCR) system to detect CK20 mRNA in thyroid carcinomas, benign thyroid diseases and peripheral blood to improve diagnosis of thyroid carcinoma and to detect disseminated tumour cells. Frozen tissue samples of 46 thyroid carcinomas and 30 benign thyroid diseases (14 multinodular goiters, 14 follicular adenomas, two Hashimoto's thyroiditis) were obtained intraoperatively. Preoperative blood samples were drawn from 31 patients with thyroid cancer, nine patients with benign thyroid disorders and 20 healthy volunteers. Nine out of nine medullary, 9/12 follicular, 7/19 papillary and 2/6 anaplastic carcinomas expressed CK20 transcripts. CK20 mRNA was undetectable in 30 tissue sections of benign thyroid diseases. Circulating tumour cells were found in the blood of 3/8 patients with medullary carcinoma, 2/8 patients with follicular carcinoma, 2/11 patients with papillary carcinoma and 1/4 patients with an anaplastic carcinoma. Nine blood samples of patients with benign thyroid diseases and 20 healthy volunteers tested negative. For the first time CK20 mRNA could be detected in tissue sections of thyroid carcinomas and peripheral blood samples of patients with thyroid cancer. It was not detectable in benign thyroid diseases. Our results therefore strongly suggest that CK20 RT-PCR assays may improve the diagnosis of thyroid carcinoma and is able to detect circulating tumour cells in peripheral blood of thyroid carcinoma patients.

Vascular endothelial growth factor-C gene expression in papillary and follicular thyroid carcinomas

BACKGROUND

Vascular endothelial growth factor-C (VEGF-C) is known to be related to development of lymphatic vessels. Papillary thyroid carcinoma characteristically metastasizes to regional lymph nodes, whereas follicular thyroid carcinoma commonly spreads hematogenously. The present study was designed to determine whether expression of the VEGF-C gene is related to the different metastatic features of these 2 types of thyroid carcinoma.

METHODS

Thyroid carcinoma specimens were obtained from 15 patients with papillary carcinoma and 4 patients with follicular carcinoma of the thyroid. VEGF-C gene expression was examined by Northern blotting and in situ hybridization. Immunohistochemistry was performed to localize the deposition of VEGF-C protein.

RESULTS

The ratios of VEGF-C gene expression determined by Northern blot analysis were significantly higher in papillary than in follicular carcinoma. Nonmalignant thyroid tissue from patients with papillary carcinoma also expressed higher levels of VEGF-C than tissue from patients with follicular carcinoma. Expression of the VEGF-C gene was observed by in situ hybridization in cells of papillary thyroid carcinoma but not in those of follicular carcinoma. Positive staining with antibody against VEGF-C was detected in papillary cancer cells.

CONCLUSIONS

Concurrent overexpression of the VEGF-C gene by both tumor cells and the surrounding tissue may be related to the prevalence of intrathyroidal spread through lymphatics and regional lymph node metastasis in patients with papillary thyroid carcinoma.

Blood group antigens in differentiated thyroid neoplasms

Alteration of cell-surface blood group antigens during malignant transformation is a well-known phenomenon that has not yet been sufficiently investigated in thyroid gland neoplasms. We evaluated 50 normal thyroid glands and 141 differentiated thyroid neoplasms (29 follicular adenomas, 30 follicular carcinomas, 56 papillary carcinomas, and 26 medullary carcinomas) both by the immunoperoxidase technique, using monoclonal antibodies against blood group antigens (A, B, H, Le(a), Le(b), Le(x), and Le(y)) and precursor substances (T, Tn, and sTn), and by affinity to the lectin from Arachis hypogea, to determine the usefulness of these antigens as tumor markers and prognostic factors. Neoplastic tissues showed immunostaining with concordant and nonconcordant expression of ABH antigens. There were statistically significant differences between normal and neoplastic tissues but not among the different neoplasms. Statistically significant differences in Lewis antigen expression were noted between normal and neoplastic tissues and between benign and malignant tumors. Tn and sTn antigen expression showed statistically significant differences between normal and neoplastic tissues. In conclusion, blood group antigens are tumor markers that are expressed more frequently in malignant than in benign neoplasms. The presence of metastases was correlated with enhanced peanut lectin receptors and a loss of A or B antigens.

Detection of high mobility group I HMGI(Y) protein in the diagnosis of thyroid tumors: HMGI(Y) expression represents a potential diagnostic indicator of carcinoma

Hyperplastic or neoplastic proliferative lesions of thyroid follicular epithelium consist of a spectrum, ranging from nodular hyperplasia to undifferentiated (anaplastic) carcinoma, and usually present as palpable thyroid nodules. Thyroid nodules are a common occurrence in the general population, but only a small proportion of them are eventually diagnosed as carcinoma. The difficulty in objectively identifying those thyroid nodules that are malignant to avoid unnecessary surgery, combined with the range and effectiveness of the available therapeutic options in those patients who do, indeed, have thyroid carcinoma, has prompted the search for tumor markers and prognostic indicators. The high mobility group I (HMGI) proteins represent a class of nuclear proteins involved in the regulation of chromatin structure and function. HMGI(Y), one of the members of this class, is expressed at high levels during embryogenesis and in malignant tumors but at generally low levels in normal adult human tissues. Previous work on a limited number of thyroid samples suggested that the detection of the HMGI(Y) proteins may provide a clinically useful diagnostic tool. To verify this assumption, we analyzed HMGI(Y) expression by a combination of immunohistochemistry and reverse transcription-PCR in 358 thyroid tissue samples that were representative of the spectrum of thyroid tumor pathology. HMGI(Y) was detectable in 18 of 19 follicular carcinomas, 92 of 96 papillary carcinomas, and 11 of 11 undifferentiated (anaplastic) carcinomas but in only 1 of 20 hyperplastic nodules, 44 of 200 follicular adenomas, and 0 of 12 normal tissue samples. The correlation between HMGI(Y) expression and a diagnosis of carcinoma was highly significant (P < 0.0001). We also prospectively collected and analyzed for HMGI(Y) expression by immunohistochemistry and reverse transcription-PCR in 12 fine needle aspiration biopsies from 10 patients who subsequently underwent surgical removal of a solitary thyroid nodule. HMGI(Y) was detectable only in the four fine needle aspiration biopsies, corresponding to the thyroid nodules that were definitively diagnosed as carcinomas after surgery (two follicular carcinomas and two papillary carcinomas). The remaining eight samples (six follicular adenomas and two samples consisting of normal follicular cells) were negative. The findings of this study confirm the differential expression of HMGI(Y) in thyroid neoplasia and indicate the HMGI(Y) protein as a potential marker for thyroid carcinoma.

Galectin-3 is a presurgical marker of human thyroid carcinoma

Galectin-3 is a carbohydrate-binding protein endowed with an affinity for beta-galactosides. It has been shown to play an important role in cell-cell and cell-matrix interactions and in pre-mRNA splicing. Furthermore, it is involved in the control of cell growth, neoplastic transformation, and metastasis. Interestingly, high levels of galectin-3 expression have been recently described in malignant thyroid neoplasias, but not in adenomas or in normal thyroid tissue. We investigated galectin-3 expression in human presurgical specimens obtained by fine-needle aspiration biopsy. We analyzed galectin-3 expression by immunoperoxidase staining in both paraffin-embedded cytological thyroid sediments (cell blocks) obtained by fine-needle aspiration biopsy and their histological counterparts. A total of 64 samples were examined: 17 follicular carcinomas; 18 papillary carcinomas; and 29 follicular adenomas. All cell blocks and histological samples of papillary carcinomas expressed high levels of galectin-3 at either the cytoplasmic or nuclear level. Among follicular carcinomas, all histological samples expressed galectin-3, whereas 14 of 17 corresponding cell blocks were positive in the cytoplasm. No evidence of cytoplasmic galectin-3 expression was observed in 26 of 29 follicular adenomas. Hence, cytoplasmic galectin-3 staining seems to be a reliable, easy, and cheap marker for presurgical diagnosis of follicular carcinomas and an even more suitable one for papillary carcinomas.