Papillary microcarcinoma of the thyroid gland: is the immunohistochemical expression of cyclin D1 or galectin-3 in primary tumour an indicator of metastatic disease?

The Combined Utility of HBME-1 and Galectin-3 Immunohistochemistry and BRAF V600E Mutations in the Diagnosis of Papillary Thyroid Carcinoma

Newer diagnostic modalities have revolutionized the pathologist’s approach to diagnosing thyroid malignancies. Molecular characterization of these malignancies has helped circumvent common morphologic diagnostic difficulties by integrating their genotypic, phenotypic, and immunohistochemical features. BRAF V600E mutation has been characterized as highly specific for thyroid carcinoma, especially papillary thyroid carcinoma (PTC); human bone marrow endothelial marker-1 (HBME-1) and galectin-3 are also such markers that are highly specific for PTC. We propose to study HBME-1 and galectin-3 expression and BRAF V600E mutation in thyroid neoplasms and do a comparative analysis to determine whether there is a correlation between BRAF V600E expression and that of HBME-1 and galectin-3. We further propose to analyze the individual and combined diagnosed utility of the above-mentioned ancillary diagnostic techniques.

Ki-67 and CK-19 are predictors of locoregional recurrence in papillary thyroid carcinoma

Most patients with papillary thyroid carcinoma have good prognosis; however, recurrence rates and the need of salvage treatment remain a significant problem for 5-40% of patients. Although several risk classifications based on clinicopathological prognostic factors are used, it is not possible to predict which patients will have a higher risk of recurrence. The objective of the study is to analyse the impact of cytokeratin-19 and Ki-67 immunoexpression as predictive markers of the risk of recurrence in papillary thyroid carcinoma. This is a retrospective case-control study, including 42 patients with papillary thyroid carcinoma and 42 controls. The groups were matched by gender, age and pathological staging T and N. Slides were made by the microarray tissue system. Multivariate logistic regression was applied to identify an independent risk factor for recurrence. Of the 42 selected cases, 30 patients (71.4%) were female and 12 (28.6%) were male, ranging in age from 10 to 80 years (median of 39 years). Most patients (64.3%) had tumors at initial T staging (T1-T2). Half of the sample was classified as low risk according to the American Thyroid Association (ATA) risk stratification. Follow-up time ranged from 46 to 196 months, with time to recurrence from 2 to 106 months (median, 30 months). CK-19 and Ki-67 immunoexpression had a statistically significant association with the risk of recurrence (p = 0.029 and p = 0.007, respectively). In multivariate logistic regression analysis, immunoexpression for these markers was an independent risk factor for locoregional recurrence (OR-9,64; CI-1.14-81.01 and OR-3,21; CI-1.32-7.94, respectively). The immunohistochemical analysis of the Ki-67 and CK-19 markers is useful to predict tumour recurrence in patients with papillary thyroid carcinoma.

Diagnostic significance of CK19, galectin-3, CD56, TPO and Ki67 expression and BRAF mutation in papillary thyroid carcinoma

The aim of the present study was to examine the rate of BRAF mutation and the expression profiles of CK19, galectin-3, CD56, thyroid peroxidase (TPO) and Ki67 in papillary thyroid carcinoma (PTC) and papillary thyroid micro-carcinoma (PTMC). A total of 246 cases of thyroid disease were collected, including PTC, PTMC, nodular goiter (NG) and Hashimoto thyroiditis (HT). The results revealed that CK19 expression was 116/120 in PTC, 61/64 in PTMC, 2/34 in NG and 1/28 in HT. Galectin-3 positive expression was 115/120 in PTC, 60/64 in PTMC, 6/34 in NG and 4/28 in HT. TPO positive expression was 8/120 in PTC, 1/64 in PTMC, 30/34 in NG and 25/28 in HT. CD56-positive expression was 12/120 in PTC, 3/64 in PTMC, 33/34 in NG and 26/28 in HT. Ki67 labeling index was 2.52±0.46% in PTC (120 cases), 2.62±0.52% in PTMC (64 cases), 2.55±0.44% in NG (34 cases) and 2.58±0.48% in HT (28 cases). BRAF mutation rate was 93/120 in PTC, 47/64 in PTMC, 3/34 in NG and 2/28 in HT. These results suggested that expression patterns of CK19, galectin-3, CD56 and TPO and BRAF mutation exhibit diagnosis value in thyroid disease. However, Ki67-positive rate exhibits no notable diagnosis value in thyroid disease.

The Genetics of Papillary Microcarcinomas of the Thyroid: Diagnostic and Prognostic Implications

Papillary microcarcinoma of the thyroid (mPTC) is defined by the WHO as a papillary thy-roid cancer measuring 10mm or less in diameter and it is nowadays a topic of intense debate among the members of the medical community due to its apparent “epidemic” rise. Although these tumors follow almost always an indolent clinical course and carry an excellent prognosis, it is known that a small sub-set may display a potentially aggressive behavior. Nevertheless, we still lack an accurate way of predict-ing those which will cause significant disease. In an attempt to address this problem, a number of clini-co-pathologic features have been studied as poor prognostic markers in mPTC, and their association with known genetic alterations in thyroid cancer has been evaluated. Herein we review the present knowledge concerning mPTC’s genetic profile, namely the prevalence of BRAF (V600E), RAS and TERT promoter mutations and RET/PTC and PAX8-PPARG rearrangements and report the results of the evaluation in the putative prognostic value of these genetic alterations in mPTC.

Clinical aggressiveness of incidental and non-incidental thyroid cancer

BACKGROUND

With the increasing use of thyroid ultrasound, the recognition of thyroid nodules in a large proportion of apparently healthy subjects has become common. Because also the papillary thyroid microcarcinomas (PTMC) are being increasingly discovered, it is important to ascertain whether PTMC may exhibit heterogenous clinical features, associated with different aggressiveness.

AIM

We retrospectively examined 122 subjects [98 female (80.3%), and 24 male (19.7%)] with thyroid cancer to find potential clinical and pathological findings that could be predictive of clinically aggressive behavior.

RESULTS

Twenty of the 31 patients with true incidental cancer (64.5%) in comparison to 20 of the 91 patients with non-incidental cancer (21.9%) had a diameter <10 mm, and this difference was statistically significant (p<0.0001). There was a statistically significant association between size and invasiveness because 19.3% of invasive cancers were <10 mm whereas 44.6% of non-invasive cancers were <10 mm (p=0.005). The relationship between incidental discovery and invasiveness was also evaluated, but the proportion of incidental invasive cancer (19.3%) was not significantly different from that of incidental non-invasive cancer (30.8%). In the multivariate analysis, only size <10 mm (odds ratio=0.35, p=0.013) and papillary vs other histotypes (odds ratio=0.35, p=0.04) were statistically significant protective factors against invasiveness.

CONCLUSIONS

a) Incidentally discovered thyroid cancers are more frequently microcarcinomas; b) there appears to be no difference in terms of invasive behavior between incidental and non-incidental thyroid cancer; c) smaller tumor size emerges as a protective factor.

Warthin tumor-like papillary thyroid carcinoma with a minor dedifferentiated component: report of a case with clinicopathologic considerations

Warthin tumor-like papillary thyroid carcinoma is an uncommon variant of papillary thyroid carcinoma. We report a rare case of Warthin tumor-like variant of papillary thyroid carcinoma with a dedifferentiated component consisting of a solid tumor area composed of neoplastic cells with a spindle to tall cell morphology associated with marked nuclear pleomorphism, atypical mitoses, and foci of necrosis. Although our patient presented with a locally aggressive disease (T3 N1b Mo), she is disease-free without radioiodine therapy after a 23-month follow-up period. We emphasize that Warthin tumor-like papillary thyroid carcinoma, like other morphological variants of papillary carcinoma, may occasionally undergo dedifferentiation. As this component may be only focally detectable, we suggest an extensive sampling of all large-sized (>3 cm) papillary thyroid carcinoma. Recognition of any dedifferentiated component in a Warthin tumor-like papillary thyroid carcinoma should be reported, including its percentage, because it may reflect a more aggressive clinical course.

Diagnostic utility of galectin-3 in thyroid cancer

Galectin-3 (Gal-3), which has received significant recent attention for its utility as a diagnostic marker for thyroid cancer, represents the most well-studied molecular candidate for thyroid cancer diagnosis. Gal-3 is a protein that binds to beta-galactosidase residues on cell surface glycoproteins and has also been identified in the cytoplasmic and nuclear compartment. This marker has been implicated in regulation of normal cellular proliferation and apoptosis, as well as malignant transformation and the metastasis of cancer cells. We here present a mechanistic review of Gal-3 and its role in cancer development and progression. Gal-3 expression studies in thyroid tissue and cytologic tumor specimens and their methodological considerations are also discussed in this article. Despite great variance in their methodology, the majority of immunohistochemical studies found that Gal-3 was differentially expressed in thyroid carcinoma compared with benign and normal thyroid specimens, suggesting that Gal-3 is a good diagnostic marker for thyroid cancer. Recent studies have also demonstrated improved methodological reliability. On the other hand, Gal-3 genomic expression studies have shown inconsistent results for diagnostic utility and are not recommended. Overall, the development of Gal-3 as a diagnostic marker for thyroid cancer represents a promising avenue for future study, and its clinical application could significantly reduce the number of diagnostic thyroid operations performed for cases of indeterminant fine needle aspiration biopsy cytology, and thus positively impact the current management of thyroid nodular disease.

Increased incidence of papillary thyroid microcarcinoma with decreased tumor size of thyroid cancer

The prevalence of papillary thyroid microcarcinoma (PTMC) in thyroid cancer varies from 20.0% to 42.8% with a mean of 30.0%. Most of these patients have benign clinical courses and receive less aggressive therapeutic procedures in most medical centers. This study retrospectively reviewed 30 years data in one institute and compared it with recent publications to illustrate change in trends and influence of PTMC. Incidental PTMC is usually diagnosed as a postoperative microcarcinoma following thyroidectomy for presumably benign thyroid lesions. Subtotal thyroidectomy or lobectomy without radioactive iodide treatment is sufficient to treat incidental PTMC. In contrast, aggressive surgical treatment with (131)I therapy is indicated for non-incidental PTMC. Those with PTMC in the absence of extra-thyroid invasion diagnosed by postoperative permanent section received follow-up if they had initially received subtotal thyroidectomy. In long-term follow-up studies, cancer-specific mortality for PTMC ranged from 0% to 4%. Most of the mortality cases had distant metastasis at the time of surgery. The clinical course and therapeutic strategies for the non-incidental PTMC patients depend on the TNM stage at the time of diagnosis. One-third of PTMC with clinically aggressive behavior cannot be treated as indolent disease. Invasive tumor markers or larger tumor size are useful to predict tumor recurrence or distant metastasis for PTMC.