Fine-needle aspiration biopsy of papillary thyroid carcinoma

Systematic Review and Meta-Analysis to Identify the Immunocytochemical Markers Effective in Delineating Benign from Malignant Thyroid Lesions in FNAC Samples

Conventional cytology-based diagnosis for thyroid cancer is limited with more than 30-45% of nodules categorized as indeterminate, necessitating surgery for confirming or refuting the diagnosis. This systematic review and meta-analysis were aimed at identifying immunocytochemical markers effective in delineating benign from malignant thyroid lesions in fine needle aspiration cytology (FNAC) samples, thereby improving the accuracy of cytology diagnosis. A systematic review of relevant articles (2000-2021) from online databases was carried out and the search protocol registered in PROSPERO database (CRD42021229121). The quality of studies was assessed using QUADAS-2. Review Manager 5.4.1 from Cochrane collaboration and MetaDisc Version 1.4 was used to conduct the meta-analysis. Bias in the studies were visually analyzed using funnel plots, and statistical significance was evaluated by Egger's test. Systematic review identified 64 original articles, while meta-analysis in eligible articles (n = 41) identified a panel of 5 markers, Galectin-3, HBME-1, CK-19, CD-56, and TPO. Assessment of the diagnostic performance revealed that Gal-3 (sensitivity: 0.81; CI: 0.79-0.83; specificity: 0.84; CI: 0.82-0.85) and HBME-1 (sensitivity: 0.83; Cl: 0.81-0.86; specificity: 0.85; CI: 0.83-0.86) showed high accuracy in delineating benign from malignant thyroid nodules. Efficacy analysis in indeterminate nodules showed Gal-3 and HBME-1 have high specificity of 0.86 (CI 0.84-0.89) and 0.82 (CI 0.78-0.86), respectively, and low sensitivity of 0.76 (CI 0.72-0.80) and 0.75 (CI 0.70-0.80), respectively. Diagnostic odds ratio (DOR) of Galectin-3 and HBME-1 were 39.18 (CI 23.38-65.65) and 24.44 (CI 11.16-53.54), respectively. Significant publication bias was observed for the markers Galectin-3 and CK-19 (p < 0.05). The panel of 5 markers identified from this meta-analysis are high-confidence candidates that need to be validated in thyroid cytology to establish their efficacy and enable clinical applicability.

HBME1 and CK19 expression in non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) vs other follicular patterned thyroid lesions

BACKGROUND

Thyroid neoplasms with follicular architecture can have overlapping morphologic features and pose diagnostic confusion among pathologists. Various immunohistochemical stains have been investigated as potential diagnostic markers for PTC, among which HBME1 and CK19 have gained popularity. Non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) poses similar diagnostic challenges with interobserver variability and is often misdiagnosed as adenomatoid nodule or follicular adenoma. This study aims to evaluate expression of HBME1 and CK19 in NIFTPs in comparison to other well-differentiated thyroid neoplasms and benign mimickers.

METHOD

Seventy-three thyroid cases diagnosed over a period of 3 years at Methodist University Hospital, Memphis, TN, USA, were included in this study: 9 NIFTP; 18 papillary thyroid carcinoma (PTC); 11 follicular variant of papillary thyroid carcinoma, invasive (I-FVPTC); 24 follicular adenomas (FA); and 11 multinodular goiters/adenomatoid nodules (MNG). A tissue microarray (TMA) was constructed and HBME1 and CK19 immunohistochemistry was performed.

RESULTS

77.8% of NIFTPs, 88.9% of PTCs, 81.8% of I-FVPTCs, 16.7% of FAs, and 18.2% of MNGs showed HBME-1 expression. 66.7% of NIFTPs, 83.3% of PTCs, 81.8% of I-FVPTCs, 33.3% of FAs, and 45.4% of MNGs expressed CK19. Difference in expression of HBME1 and CK19 was statistically significant for NIFTP vs FA (qualitative; p < 0.05) and NIFTP vs MNG (p < 0.05). No statistically significant difference was found for HBME1 in NIFTP vs PTC (conventional and FVPTC), p ≥ 0.2. Sensitivity of HBME1 and CK19 for NIFTP were 78% and 67%, ~ 88% each for PTC, and 89% and 100% for FVPTC, respectively, while specificity of HBME1 and CK19 for NIFTP were 53% each, ~ 62% each for PTC, and ~55% each for FVPTC.

CONCLUSION

Our study indicated that HBME1 and CK19 are valuable markers in differentiating NIFTPs from morphologic mimics like follicular adenoma and adenomatoid nodules/multinodular goiter. While HBME1 and CK19 are both sensitive in diagnosing lesions with PTC-like nuclear features, CK19 stains a higher number of benign lesions in comparison to HBME1. No increase in sensitivity or specificity in diagnosis of NIFTP, PTC, or FVPTC was noted on combining the two antibodies.

Diagnostic Value of TROP-2 and CK19 Expression in Papillary Thyroid Carcinoma in Both Surgical and Cytological Specimens

Papillary thyroid carcinoma (PTC) represents the most common primary malignant thyroid tumor and its diagnosis is dependent on the presence of classic nuclear features that are sometimes seen in some non-neoplastic and benign lesions. Several immunohistochemical markers are used individually or in combination to help in differentiation of PTC from mimickers. The aim of the current study was to assess the diagnostic value of TROP-2 and cytokeratin 19 (CK19) expression in differentiating PTC from other mimickers both singly and in combination. The current study was carried out on 77 surgical specimens (56 PTC and 21 non-neoplastic cases) and 12 cytological specimens (4 THY2, 6 THY4, and 2 THY5). TROP-2 was negative in 81% of non-neoplastic surgical specimens and in 100% of THY2 cytological specimens while it was positive in 71.4% of PTC surgical specimens and 100% of THY4/THY5 cytological specimens. Sensitivity and specificity of TROP-2 positive expression for diagnosis of PTC in surgical specimens reached 71% and 81%, respectively, while it reached 100% for both in cytological specimens. Cytokeratin 19 showed positive expression in 85.7% of non-neoplastic surgical specimens and in 92.9% of PTC surgical specimens. Cytokeratin 19 showed negative expression in 75% of Thy2 cases while it was positive in all studied Thy4 and Thy5 cases. Sensitivity and specificity of CK19 total estimated score for diagnosis of PTC in surgical specimens were 78.6% and 66.7%, respectively, while it reached 100% and 75% in cytological specimens. Positive TROP-2 and CK19 expression in PTC were associated with lymph node metastasis. TROP-2 is a specific rather than sensitive marker while CK19 is a sensitive rather than specific marker in differentiating PTC from other mimickers in surgical specimens. The diagnostic validity of both markers was superior in diagnosis of classic PTC compared with follicular variant PTC. TROP-2 is superior to CK19 in diagnosis of PTC in cytological specimens. Both TROP-2 and CK19 could be used preoperatively in adjunct to hematoxylin and eosin for more confident diagnosis of thyroid cytology and along with radiology as predictors of lymph node metastasis.

Circulating Cytokeratin 19 Fragments in Patients with benign Nodules and Carcinomas of the Thyroid Gland

Cytokeratin 19 (CK19) is an acidic protein of 40 kDa that is part of the cytoskeleton of epithelial cells and is highly expressed by differentiated thyroid carcinomas, mainly of the papillary subtype. The soluble fragments of CK19 (Cyfra 21.1) can be measured by immunometric assays employing specific monoclonal antibodies. The present study was planned to assess the serum expression of Cyfra 21.1 in patients with benign thyroid nodules and thyroid malignancies. We enrolled 135 patients with histologically proven benign thyroid nodules (n=79) and thyroid carcinomas (n=56). No differences were found in serum Cyfra 21.1 levels between patients with benign nodules and patients with carcinomas. When thyroid malignancies were subdivided according to tumor histology, serum Cyfra 21.1 increased significantly from classical differentiated thyroid carcinomas (papillary or follicular) to less differentiated or undifferentiated carcinomas (poorly differentiated or anaplastic). CK19 release into the bloodstream is strongly related to the apoptotic pathway, and particularly to hyperproliferation-related apoptosis. These pathways characterized anaplastic and poorly differentiated thyroid carcinoma but not classical forms of differentiated thyroid carcinoma. Consequently, Cyfra 21.1 may be regarded as a circulating marker of poorly differentiated and anaplastic thyroid carcinoma. Additionally, a role of Cyfra 21.1 as a dedifferentiation marker in patients with classical differentiated thyroid carcinomas may be postulated and should be explored by further focused studies.

The reliability of fine-needle aspiration biopsy in terms of malignancy in patients with Hashimoto thyroiditis

The aim of this study was to analyze the presence of malignancy in patients with Hashimoto's thyroiditis and to investigate the reliability of preoperative fine-needle aspiration biopsy (FNAB). The retrospective study included 44 patients who were operated on for nodular goiter between December 2010 and October 2011. The patients underwent thyroidectomy following a cytologic analysis plus FNAB. Hashimoto's thyroiditis was confirmed on histopathology in all patients. FNAB results were defined as benign in 14 (31.8%), suspicion for malignancy in 17 (38.6%), malignant in 9 (20.5%), and inadequate in 4 (9.1%). Following the thyroidectomy, presence of papillary thyroid carcinoma and follicular variant of papillary thyroid carcinoma were detected in 10 patients (22.7%) and 1 (2.3%) patient, respectively. The FNAB results were interpreted in terms of malignancy, which revealed the sensitivity as 80%; specificity, 40%; false positives, 69.2%; false negatives, 14.3%; positive predictive value, 31.8%; negative predictive value, 85.7%; and diagnostic accuracy, 50%. The coexistence of Hashimoto's thyroiditis with papillary thyroid carcinoma is quite common. The FNAB results for such cases are hard to evaluate, and they are likely to increase the number of false positives.

CK19 is a sensitive marker for yolk sac tumours of the testis

Background

Malignant germ cell tumours are the most common malignant tumours in young men. They are histologically divided into seminomas and non-seminomas. Non-seminomas are further subdivided into embryonic carcinomas, yolk sac tumours, chorionic carcinomas, and teratomas. For the therapeutic management it is essential to differentiate between these histological subtypes.

Methods

Investigated cases included normal testis (n = 50), intratubular germ cell neoplasia (n = 25), seminomas (n = 67), embryonic carcinomas (n = 56), yolk sac tumours (n = 29), chorionic carcinomas (n = 2), teratomas (n = 7) and four metastases of YST’s for their CK19 expression. In addition Leydig cell- (n = 10) and Sertoli cell- tumours (n = 4) were included in this study.

Results

All investigated seminomas, embryonic carcinomas as well as normal testis and intratubular germ cell neoplasias did not express CK19. In contrast, all investigated yolk sac tumours strongly expressed CK19 protein. These findings became also evident in mixed germ cell tumours consisting of embryonic carcinomas and yolk sac tumours, although CK19-expression could also be observed in analysed chorionic carcinomas and epithelial components of teratomas.

Conclusion

CK19 proved to be a sensitive marker to identify yolk sac tumours of the testis and to distinguish them from other germ cell tumours, especially seminomas and embryonic carcinomas.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/4075546891400979.

Diagnostic criteria of well differentiated thyroid tumor of uncertain malignant potential; a histomorphological and immunohistochemical appraisal

BACKGROUND

Well differentiated thyroid tumor of uncertain malignant potential (WDT-UMP) represents a true "gray zone" of "follicular patterned" thyroid lesions, that needs to be characterized in order to outright the diagnosis of carcinoma and avoid unnecessary aggressive treatment.

AIM

To emphasize on the histomorphological criteria for more accurate diagnosis of WDT-UMP. Also to compare the immunohistochemical expression of CK19 of WDT-UMP versus adenoma and papillary thyroid carcinoma (PTC).

MATERIALS AND METHODS

The study included 60 thyroid specimens; 18 WDT-UMPs, 24 PTC (18 classic variant and 6 follicular variants) and 18 benign thyroid lesions (8 adenoma, 6 Hashimoto's thyroiditis and 4 hyperplastic nodules). H&E stained sections were assessed according to the published major and minor criteria of malignancy in the thyroid. CK 19 immunostaining was examined and evaluated according to the proportion and intensity scores.

RESULTS

We could detect the absence of nuclear inclusions, presence of characteristic nuclear groove, nuclear clearing, ovoid nuclei, nuclear crowdness, nuclear enlargement and pleomorphism as important reliable features for diagnosis of WDT-UMP with p value (<0.0001 for each). WDT-UMP showed moderate to strong CK 19 immunostaining with proportion scores 3 and 4; an intermediate expression profile; higher than adenoma and less than papillary carcinoma (p<0.0001).

CONCLUSION

The constellations of both major and minor criteria of malignancy are important clues for WDT-UMP diagnosis which could be ascertained by CK 19 immunostaining.

Study of the histological profile of papillary thyroid carcinomas associated with Hashimoto's thyroiditis

OBJECTIVE

To investigate the association between the histological parameters of papillary thyroid cancer (PTC) and the presence of Hashimoto's thyroiditis (HT).

MATERIALS AND METHODS

Histological samples from patients with PTC were reviewed by an endocrine pathologist. The following parameters were analyzed: presence of concomitant HT, multifocality, presence of nodal metastasis, tumor size, vascular invasion, perineural infiltration, histological variant, and pathological staging. Clinical data included gender and age at the time of the diagnosis.

RESULTS

A total of 94 cases of PTC were reviewed. There was a predominance of women (85.1% vs. 14.9%) and median age at presentation was 45.13 years. The presence of HT was significantly associated with greater occurrence of multifocal tumors (p = 0.004), early pathological stage (p = 0.02), and smaller tumor size (p = 0.025).

CONCLUSIONS

Patients with PTC associated with HT had significantly smaller tumors, more often multifocal and in an earlier stage than their counterparts without HT. A better understanding of the immune response involved in these tumors may be useful for future strategies on the prevention and for the development of new therapeutic approaches for this group of neoplasms.

Role of p53 and β-catenin mutations in conjunction with CK19 expression on early tumor recurrence and prognosis of hepatocellular carcinoma

BACKGROUND

Cytokeratin 19 (CK19), a molecular marker of hepatic progenitor cells and cholangiocytes, is expressed in hepatocellular carcinomas (HCC), but not in normal hepatocytes. However, role of CK19 in HCC progression, especially when interacted with p53 and β-catenin mutations, remained largely unknown.

MATERIALS AND METHODS

From January 1983 to December 1997, 210 surgically resected, unifocal, primary HCCs were studied retrospectively. CK19 protein expression was detected by immunohistochemistry while mutations of p53 and β-catenin genes were detected by direct DNA sequencing.

RESULTS

CK19 protein expression was detected in 35.7% (75/210), p53 mutation in 47.2% (83/176) and β-catenin mutation in 14.5% (27/186). The tumor size (p=0.0023), grade (p  = 0.00093), tumor stage (p  = 4  x  10-7), high α-fetoprotein (p=0.0004), p53 mutation (p  = 0.024), absence of β-catenin mutation (p  =  0.0013), and CK19 expression (p  =  3 x 10-5) were markers predictive of early tumor recurrence (ETR). CK19 expression, stage, and ETR were strong indicators of poor prognosis (all p  <  0.0001). Importantly, combination analysis showed an additive unfavorable prognostic interaction of CK19 expression and p53 mutation. On the contrary, concurrent CK19 expression and β-catenin mutation was rare and CK19 expression abolished the suppression effect of β-catenin mutation on HCC progression.

CONCLUSIONS

CK19 expression is associated with more aggressive HCC. CK19 cooperates with p53 mutation towards advanced disease. In contrast, CK19 expression and β-catenin mutation play dramatic opposite roles in vascular invasion, ETR and the prognosis of HCC.

Absence of the BRAF mutation in HBME1+ and CK19+ atypical cell clusters in Hashimoto thyroiditis: supportive evidence against preneoplastic change

An association between Hashimoto thyroiditis and papillary thyroid carcinoma has been postulated for decades. We undertook this study to identify potential precursors of papillary thyroid carcinoma in Hashimoto thyroiditis using a combination of morphologic, immunohistochemical, and molecular techniques. For the study, samples from 59 cases of Hashimoto thyroiditis were stained with antibodies to HBME1 and cytokeratin (CK)19. Tiny HBME1+ and CK19+ atypical cell clusters were identified and analyzed for the BRAF mutation by the colorimetric Mutector assay and allele-specific polymerase chain reaction. HBME1+ and CK19+ atypical cell clusters were identified in 12 (20%) of 59 cases. The minute size (<1 mm) of the clusters and the incomplete nuclear changes precluded a diagnosis of papillary microcarcinoma. The atypical cell clusters from all 12 cases were negative for BRAF. The absence of the BRAF mutation in these atypical cell clusters suggests that they may not be preneoplastic. Caution should be exercised in interpreting positive HBME1 or CK19 staining in Hashimoto thyroiditis.

Clinical implications of molecular markers in follicular cell-derived thyroid cancer

The increasing use/applications of molecular biology techniques have provided new insights on the genetic changes that underlie carcinogenesis and tumor progression in thyroid cancer. Molecular analysis may improve the histopathologic evaluation of follicular cell-derived thyroid carcinoma, not only elucidating some unresolved problems related to the diagnosis and disease prognosis, but also by improving patient management. Besides increasing our comprehension of cancer biology, either genetic alterations or gene expression profiles implicated in thyroid carcinogenesis shed new light on innovative diagnostic procedures as well as on targeted therapies.

Differential expression of galectin-3, CK19, HBME1, and Ret oncoprotein in the diagnosis of thyroid neoplasms by fine needle aspiration biopsy

Background:

Fine needle aspiration biopsy (FNAB) is a common and excellent procedure for the evaluation of thyroid lesions that require surgical resection. At times, the FNAB diagnosis can be difficult, particularly of follicular-patterned lesions. Previous studies have shown that some immunohistochemical (IHC) markers may be helpful in establishing more accurate diagnosis. In this study, our goal was to evaluate four of the recently investigated markers in differentiating benign from malignant thyroid nodules on FNABs.

Materials and Methods:

We performed IHC staining of galectin-3, Ret oncoprotein (Ret), HBME-1, and cytokeratin 19 (CK19), on cell block sections of thyroid FNAB cases that had corresponding surgical resections. They included 44 benign lesions (37 hyperplastic or cellular nodules, HN; and 7 follicular adenomas, FA) and 27 malignant tumors (6 follicular carcinoma, FC; 19 classic papillary carcinoma, PTC; and 2 follicular variant of papillary carcinoma, FVPC). The stains were done according to the standard avidin–biotin–peroxidase method.

Results:

Statistical analysis showed that immunoexpression was significantly higher in the malignant group for all four markers. The sensitivity for positive expression for all benign lesions versus malignant tumors was as follows: 10/44 (22.7%) versus 25/27 (92.6%) for galectin-3; 14/44 (31.8%) versus 23/27 (85%) for Ret; 12/44 (27.3%) versus 24/27 (88.8%) for HBME-1; and 13/44 (29.5%) versus 23/27 (85%) for CK19. The sensitivity and specificity was highest for galectin-3 (92.6% and 77.3%, respectively) followed by HMBE-1 (88.9% and 72.7%, respectively). When combining the markers' expressions, the panel of galectin-3 + HBME-1 showed the highest sensitivity and specificity (90.7% and 75%, respectively), but this was, however, lower than galectin-3 alone (92.3% and 77.3%, respectively).

Conclusion:

We conclude that galectin-3 is the best single marker in differentiating benign from malignant thyroid lesions with the highest sensitivity and specificity. The galectin-3 + HBME-1 was the best combination for distinguishing benign from malignant lesions. Because they were the best two independent and combined markers, we recommend the use of the galectin-3 + HBME-1 panel to enhance the diagnostic accuracy of follicular-patterned thyroid lesions on FNABs.

Cytomorphologic features of poorly differentiated thyroid carcinoma: a multi-institutional analysis of 40 cases

BACKGROUND

Poorly differentiated thyroid carcinoma (PDTC) is an uncommon and aggressive malignancy. Despite the significant clinical implications of a diagnosis of PDTC, its cytomorphologic features have not been well defined. Statistical analysis was applied to a series of 40 PDTCs to identify a specific set of cytomorphologic features that characterized these tumors on fine-needle aspiration biopsy (FNAB).

METHODS

In total, 40 thyroid FNABs that were highly diagnosed histologically as PDTC (19 insular carcinomas and 21 noninsular carcinomas) comprised the study group. A control group of 40 well differentiated thyroid neoplasms were selected for comparison. All FNABs were reviewed and scored for a series of 32 cytomorphologic features. The results were evaluated using univariate and stepwise logistic regression (SLR) analyses.

RESULTS

In univariate analysis, 17 cytomorphologic features were identified that characterized the 40 PDTCs: insular, solid, or trabecular cytoarchitecture (P < .001); high cellularity (P = .007); necrosis (P = .025) or background debris (P = .025); plasmacytoid appearance (P = .0007); single cells (P < .0001); high nuclear/cytoplasmic ratio (P < .0001); scant cytoplasm (P = .03); nuclear atypia (P < .0001), including nuclear pleomorphism (P = .0052) and anisokaryosis (P < .0001); granular/coarse chromatin (P = .026); naked nuclei (P = .01); mitotic activity (P = .0001) and apoptosis (P < .0001); endothelial wrapping (P = .0053); and severe crowding (P < .0001). In logistic regression analysis, severe crowding (P = .0008) and cytoarchitecture (P < .0001) were identified as the most significant cytomorphologic features of PDTCs, and the combination of cytoarchitecture, severe crowding, single cells, and high nuclear/cytoplasmic ratio was the most predictive of PDTC.

CONCLUSIONS

PDTCs have characteristic cytomorphologic features. By using logistic regression analysis, the features that were identified as the most predictive of PDTC were severe crowding, insular/solid/trabecular morphology, single cells, and high nuclear/cytoplasmic ratio.

Biomarker panel diagnosis of thyroid cancer: a critical review

The accurate preoperative diagnosis of thyroid cancer continues to be a significant challenge for those individuals who present with nodular thyroid disease, particularly for tumors with indeterminate cytomorphological features by fine-needle aspiration biopsy. In an effort to develop improved diagnostic tools, a number of studies have investigated the discriminatory potential of many different RNA and protein molecules. However, no individual thyroid cancer biomarker has been found with sufficient sensitivity and specificity. Therefore, research focus has shifted to panels of multiple markers with the hope of improved performance and robustness. A panel comprised of GAL3, CK19 and HBME1 is by far the most studied to date and offers some improvement over individual marker performance alone. However, relatively few marker panels have been studied and their performances and application as diagnostic tests have not been consistently reported. We present a comprehensive review of molecular marker panel studies for thyroid tumors and current issues and challenges. In the future, studies evaluating larger numbers of biomarkers in large patient cohorts are required for the development and validation of a clinically applicable test.

HBME-1 and CK19 are highly discriminatory in the cytological diagnosis of papillary thyroid carcinoma

The cytologic diagnosis of papillary thyroid carcinoma is straightforward in most instances. However, there are some mimics including goitrous nodules and Hurthle cell neoplasms. Many studies have shown the combination of HBME-1 and CK19 expression to be useful in reaching a correct histologic diagnosis on tissue sections. We aim to assess the value of these markers in the setting of cell blocks prepared from needle aspiration specimens. We performed immunohistochemical staining of HBME-1 and CK19 on cell block material from 22 thyroid nodules that also had follow-up histology. Both CK19 and HBME-1 were strongly positive in all nine cases of papillary thyroid carcinoma, the latter showing distinct luminal accentuation. In the non-papillary carcinomas, none showed positivity for both HBME-1 and CK19. Two of six Hurthle cell neoplasms were positive for CK19, however all were negative for HBME-1. One of nine goitrous nodules was strongly positive for HBME-1 with luminal/membranous staining, but this were negative for CK19. The sensitivity, specificity and positive predictive value of HBME-1 in distinguishing between papillary thyroid carcinoma and goitrous nodules/Hurthle cell neoplasms were found to be 100%, 92.9% and 0.9, respectively; and that of HBME-1 and CK19 combination was 100%, 100% and 1. We thus conclude that the combination of positive HBME-1 (luminal/membranous) and CK 19 (cytoplasmic) staining on cell blocks of thyroid cytologic specimens is highly discriminatory in the diagnostic workup for papillary thyroid carcinoma.

Molecular phenotyping of thyroid tumors identifies a marker panel for differentiated thyroid cancer diagnosis

BACKGROUND

Currently, a large proportion of individuals undergo thyroidectomy as a diagnostic procedure for cancer. The objective of this work was to evaluate the molecular phenotype of differentiated thyroid cancer (DTC) and benign thyroid lesions to identify molecular markers that allow for accurate thyroid cancer diagnosis.

METHODS

Tissue microarrays consisting of 100 benign and 105 malignant thyroid lesions, plus 24 lymph node samples, were stained for a panel of 57 molecular markers. Significant associations between marker staining and tumor pathology (DTC versus benign) were determined using contingency table and Mann-Whitney U (MU) tests. A Random Forests classifier algorithm was also used to identify useful/important molecular classifiers.

RESULTS

Of the 57 diagnostic markers evaluated 35 (61%) were significantly associated with a DTC diagnosis after multiple testing correction. Of these, in DTC compared with benign thyroid tumors, 8 markers were downregulated and 27 upregulated. The most significant markers for DTC diagnosis were: Galectin-3, Cytokeratin 19, Vascular Endothelial Growth Factor, Androgen Receptor, p16, Aurora-A, and HBME-1. Using the entire molecular marker panel, a Random Forests algorithm was able to classify tumors as DTC or benign with an estimated sensitivity of 87.9%, specificity of 94.0%, and an accuracy of 91.0%.

CONCLUSION

Evaluation of the DTC and benign thyroid tumor molecular phenotype has allowed for identification of a marker panel, composed of both established and novel markers, useful for thyroid cancer diagnosis. These results suggest that further study of the molecular profile of thyroid tumors is warranted, and a diagnostic molecular marker panel may potentially improve patient selection for thyroid surgery.

Application of immunohistochemistry to thyroid neoplasms

CONTEXT

Thyroid lesions with nodular architecture and follicular pattern of growth often pose difficulties in accurate diagnosis during the assessment of cytologic and histologic specimens. The diagnosis of follicular neoplasm on cytology or of follicular tumor of uncertain malignant potential on histology is likely to cause confusion among clinicians and delay effective management of these lesions. Occasionally, thyroid tumors represent unusual or metastatic lesions and their accurate diagnosis requires immunohistochemical confirmation.

OBJECTIVE

To review the literature on the applications of immunohistochemistry in the differential diagnosis of thyroid tumors.

DATA SOURCES

Relevant articles indexed in PubMed (National Library of Medicine) between 1976 and 2006.

CONCLUSIONS

Our review supports the use of ancillary techniques involving a panel of antibodies suitable for immunohistochemistry and molecular analysis in the assessment of thyroid nodules. These tools can improve diagnostic accuracy when combined with standard morphologic criteria.

The role of immunolocalization of CD57 and GLUT-1 in cell blocks in fine-needle aspiration diagnosis of papillary thyroid carcinoma

BACKGROUND

CD57 (Leu7), a marker for natural killer lymphocytes, and glucose transporter-1 (GLUT-1), a facilitative cell surface glucose transport protein, are expressed in a wide spectrum of epithelial malignancies. The usefulness of CD57 and GLUT-1 immunostaining was evaluated as an adjunct to assist in the diagnosis of papillary carcinoma in fine-needle aspirations (FNAs) of the thyroid.

METHODS

Immunohistochemical staining for CD57 and GLUT-1 was performed on paraffin-embedded cell blocks of 50 thyroid FNA cases with the following cytologic diagnoses: 1) papillary carcinoma (15 cases); 2) atypical cytology, cannot exclude papillary carcinoma (14 cases); and 3) benign thyroid (21 cases).

RESULTS

Fourteen of 15 cases with an unequivocal diagnosis of papillary carcinoma were positive for CD57 and 1 case was negative for CD57. Tissue follow-up confirmed papillary carcinoma in all 15 cases. Of the 14 cases with a diagnosis of atypical cytology, cannot exclude papillary carcinoma, 6 cases were positive for CD57 and subsequent excision confirmed papillary carcinoma in all 6 cases. The remaining 8 cases negative for CD57 included surgically confirmed goiter (5 cases), adenoma (2 cases), and papillary carcinoma (1 case). The follicular cells in all 21 cases with a cytologic diagnosis of benign thyroid were negative for CD57. Histologic follow-up of these cases confirmed the benign cytologic diagnoses. GLUT-1 was negative in all cases. The sensitivity and specificity of CD57 was 91% and 100%, respectively.

CONCLUSIONS

CD57 immunostaining is a useful adjunct for the diagnosis of papillary thyroid carcinoma in cell block material. Although negative staining for CD57 does not completely exclude papillary carcinoma, positive staining aids in the accurate diagnosis of malignancy in cytomorphologically equivocal cases. GLUT-1 did not prove to be a useful marker in distinguishing papillary carcinomas.

Cytokeratin 19 immunolocalization in cell block preparation of thyroid aspirates. An adjunct to fine-needle aspiration diagnosis of papillary thyroid carcinoma

CONTEXT

Immunohistochemical staining for cytokeratin 19 (CK-19) is a useful ancillary technique for diagnosing papillary thyroid carcinoma (papillary carcinoma) in histologic specimens. Although similar results have been obtained on aspirate smears, to our knowledge the utility of CK-19 immunolocalization in cell block preparations as an adjunct to fine-needle aspiration diagnosis of papillary carcinoma has not been examined.

OBJECTIVE

The purpose of this study was to determine whether CK-19 immunostaining of cell block preparations of thyroid aspirates is a useful ancillary technique for diagnosing papillary carcinoma.

MATERIALS AND METHODS

Using a monoclonal antibody to CK-19 and a standard avidin-biotin complex technique, immunostaining was performed on paraffin-embedded cell blocks of 57 cases with the following cytologic diagnoses: (a) papillary carcinoma (20 cases); (b) atypical cytology, cannot exclude papillary carcinoma (19 cases); and (c) nonneoplastic thyroid (18 cases). The staining reaction in each case was graded on the basis of percentage of epithelial cells stained (1+, <10%; 2+, <10%-50%; 3+, >50). Tissue follow-up was available in all cases.

RESULTS

Nineteen (95%) of 20 cases with an unequivocal diagnosis of papillary carcinoma were positive for CK-19 (3+). Tissue follow-up confirmed papillary carcinoma in all 20 cases. Of the 19 cases with a diagnosis of atypical cytology, cannot exclude papillary carcinoma, 7 (37%) cases displayed 3+ immunostaining and subsequent excision confirmed papillary carcinoma in all 7 cases. The remaining 12 cases with 1+ immunostaining included surgically confirmed goiter (6 cases), adenoma (2 cases), lymphocytic thyroiditis (3 cases), and papillary carcinoma (1 case). The follicular cells in 18 cases with a cytologic diagnosis of nonneoplastic thyroid showed 1+ immunostaining. Histologic follow-up of these cases confirmed the nonneoplastic cytologic diagnoses.

CONCLUSIONS

Cytokeratin 19 immunostaining of cell block preparations of thyroid aspirates serves as a useful tool for the diagnosis of papillary carcinoma. Strong immunostaining (3+) for CK-19 aids in accurate diagnosis of malignancy in cytomorphologically equivocal cases of papillary carcinoma.

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.

Aspiration cytology of pediatric solitary papillary hyperplastic thyroid nodule

CONTEXT

Solitary papillary hyperplastic thyroid nodules (SPHTNs) are frequently encountered in children and teenagers. Although the histologic features are well described, to the best of our knowledge, cytologic findings have not been reported.

OBJECTIVES

To review the cytologic features of histologically proven SPHTNs and to identify the potential diagnostic pitfalls in cytologic diagnosis.

MATERIALS AND METHODS

Fine-needle aspiration cytology of 3 histologically proven SPHTNs was reviewed.

RESULTS

Two girls and 1 boy (ages 11, 12, and 15 years) were affected. The cytologic diagnosis in all 3 cases was suspicious for papillary thyroid carcinoma (PTC). The spectrum of cytologic findings included broad flat sheets and 3-dimensional clusters with fire flares. There was mild to moderate nuclear pleomorphism and nuclear atypia. Short nonbranching papillae with transgressing vessels shown to represent hyperplastic papillae on histologic sections were identified in all cases. The background contained giant cells, histiocytes, and watery and inspissated colloid. Although nuclear grooves were identified in occasional cells, intranuclear inclusions were absent. A cell block section (1 case) and histologic sections of SPHTNs (2 cases) were immunohistochemically negative for cytokeratin 19.

CONCLUSIONS

Fine-needle aspiration of SPHTNs may be difficult to interpret accurately and can result in false-positive diagnosis of PTC. Although it shares several cytologic features with PTC, the presence of fire flares and short nonbranching papillae, as well as lack of intranuclear inclusions and watery and inspissated colloid in SPHTN appear to be useful features that are helpful in distinguishing SPHTN from PTC. Negative immunohistochemical staining for cytokeratin 19 is useful in excluding a diagnosis of PTC.