Well-differentiated Tumors Of Uncertain Malignant Potential Research Articles

Immune characterization of thyroid neoplasm's and its variants using immunohistochemical markers: CK-19, Galectin-3 and Hector Battifora mesothelial-1

BackgroundNodular lesions of the thyroid are amongst the common palpable lesions that are encountered by the pathologists in the fine needle aspiration clinics and not only aspiration smears, but even biopsy sections pose significant challenges in their characterization and further classification. Neoplastic lesions of the thyroid have shown a steady rise worldwide and are diagnosed at age younger than most other cancers. Histopathology remains the gold standard in diagnosis and classification of thyroid neoplasms, with variable sensitivity and specificity of immunohistochemical markers, also attributed to variation in the inclusion criteria. We classified the thyroid neoplasms based on WHO Classification (2017) and aimed to study the diagnostic utility of immunohistochemical markers - CK-19, Galectin-3 and Hector Battifora mesothelial-1 performed on manual tissue microarray sections to differentiate various variants of papillary carcinoma from its mimickers, specifically follicular patterned papillary neoplasms from other follicular patterned lesions. MethodProspective study of neoplastic lesions of thyroid from July 2018 to August 2020. Authors describe the clinico-radiological, cytological, histo-morphological and immunohistochemical features of neoplastic nodular lesions of the thyroid. ResultsProspective analysis of nodular thyroid lesions yielded 76 cases, of which 38 were neoplastic. Cytology showed discordance in 10/24 cases, amongst the discordant cases, 70% were confirmed as papillary carcinoma. CK-19 showed high expression in all variants of papillary carcinomas (24/24), low expression in well differentiated tumor of uncertain malignant potential (WD-TUMP) and medullary carcinoma. It was negative in follicular and Hurthle cell neoplasms. Galectin-3 showed 100% specificity and HBME-1 showed 100% sensitivity in diagnosis of papillary carcinoma and its variants. Adenomatoid nodules did not express Gal-3 which helped in their differentiation from FVPTC. ConclusionsGal-3 in combination either with CK-19 or HBME-1 improves the sensitivity and specificity of detection of papillary carcinoma, its variants and its differentiation from follicular patterned lesions to 100% with a significant p value.

Clinical outcomes of follicular tumor of uncertain malignant potential of the thyroid: real-world data.

Thyroid tumors arising from follicular cells can generally be divided into malignant and benign tumors. However, some cases are difficult to clearly diagnose whether they are benign or malignant. Therefore, in the most recent version of World Health Organization (WHO) classification, some borderline lesions such as follicular tumor of uncertain malignant potential (FT-UMP), well-differentiated tumor of uncertain malignant potential (WDT-UMP), and noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) were proposed. In this study, we investigated the clinical aspects, including the prognosis, of FT-UMP patients. We investigated the clinical features of 339 patients with FT-UMP. On ultrasound, 68% of the tumors were diagnosed as intermediate, and only 5% of those tumors were diagnosed as malignant. On cytology, 40% of the tumors were diagnosed as follicular neoplasm, and only 1% of these were suspected to be or diagnosed as malignancy. The diagnosis was based on questionable capsular invasion for 332 patients, questionable vascular invasion for 2 patients, and both for 5 patients. Eighty-six percent of the tumors showed low cell proliferation activity. To date, five patients (1%) have shown distant recurrence during postoperative follow-up and underwent various treatments such as radioactive iodine therapy, orthopedic surgery, and denosumab injection. None of these patients have died due to thyroid carcinoma. Our findings suggest that FT-UMP is generally an indolent disease, but some patients show distant recurrence. Physicians should carefully follow patients, although it remains unknown how long they should be observed after surgery.

Noninvasive Encapsulated Papillary RAS-Like Thyroid Tumor (NEPRAS)

Abstract Introduction: The diagnosis of thyroid tumors arising from follicular cells that are encapsulated/well delimited and noninvasive is a challenge. When unequivocal nuclear alterations are present, the final diagnosis can range from noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) and classical/encapsulated papillary thyroid cancer (PTC), including aggressive subtypes, to poorly differentiated carcinoma. As proposed recently, the presence of papillae in the absence of exuberant nuclear alterations (nuclear score 2), given that the other criteria for NIFTP are met, may not be sufficient for the diagnosis of PTC. This condition is called “noninvasive encapsulated papillary RAS-like thyroid tumor” (NEPRAS), whose nature would be borderline and not malignant. Revising our cases of tumors > 1 cm that were diagnosed previously as PTC and that were encapsulated/well delimited and noninvasive, we found three cases of NEPRAS. We now revised our cases of tumors > 1 cm diagnosed previously as well-differentiated tumor of uncertain malignant potential (WDT-UMP) because the nuclear alterations were not considered to be sufficient for the diagnosis of PTC on that occasion. Case: In a 29-year-old euthyroid male patient with a single thyroid nodule whose fine-needle aspiration had revealed indeterminate cytology, a single tumor measuring 3.2 cm was reclassified from WDT-UMP to NEPRAS. For this diagnosis, the tumor met the following criteria: encapsulation or clear demarcation, no vascular or capsular invasion, presence of papillae, < 30% solid/trabecular/insular growth pattern, no tumor necrosis or high mitotic activity, and nuclear score 2. The BRAFV600E mutation was absent. The patient continues to show no signs of recurrence 7 years after lobectomy. Conclusion: Despite the presence of papillae, some tumors may be reclassified from malignant (encapsulated PTC) to borderline (NEPRAS). This proposal would result in a change of management, with the same implications as those seen for the change from noninvasive encapsulated follicular variant of PTC to NIFTP.

Preoperative Role of RAS or BRAF K601E in the Guidance of Surgery for Indeterminate Thyroid Nodules.

RAS and K601E BRAF mutations are not a reliable indicator of malignancy in fine-needle aspirations (FNA) of thyroid indeterminate cytologic nodules. We aimed to evaluate the histologic characteristics, the risk of malignancy associated with such mutations in FNA and their potential interest for preoperative clinical management of nodules. We evaluated 69 indeterminate thyroid nodules with RAS or K601E BRAF mutations with available histopathologic follow-up. All FNA specimens were indeterminate according to the thyroid Bethesda system. Diagnosis of malignant, benign or indolent neoplasms was classified according to 2017 WHO classification. Carcinoma, NIFTP (noninvasive follicular thyroid neoplasm with papillary-like features) and WDTUMP (well-differentiated tumor of uncertain malignant potential) were considered "surgical," as they require surgical excision. Adenoma was considered "non-surgical." The risk of malignancy and the risk of "surgical disease" were evaluated. Pathologic evaluation of the 69 mutated nodules demonstrated benign, indolent and malignant histology in 17 cases (25%), 21 cases (30%) and 31 cases (45%), respectively. The risk of malignancy was 45%, and the risk of surgical disease was 75%. The majority of carcinomas were a follicular variant of papillary thyroid carcinoma. On follow-up, there have been no recurrences to date. Preoperative RAS or BRAF K601E mutations detection in cytologic indeterminate thyroid nodules carries a high risk of surgical disease and may benefit from surgical management. Most surgical lesions harboring those mutations are low-risk tumors, which may be in favor of an initial lobectomy.

Mutation profiles of follicular thyroid tumors by targeted sequencing

BackgroundOne of the major challenges remaining in the classification of thyroid tumor is the determination of whether a nodule is benign or malignant. We aimed to characterize the mutational profiles of follicular thyroid tumor and to identify markers with potential diagnostic and prognostic implications.MethodsTargeted sequencing with a panel of 18 thyroid cancer-related genes was performed on 48 tissue samples from follicular thyroid adenoma (FTA), 32 follicular tumors of uncertain malignant potential (FT-UMP), 17 well-differentiated tumors of uncertain malignant potential (WDT-UMP) and 53 samples from follicular thyroid carcinoma (FTC). The correlation of mutation profiles and clinicopathological features and prognosis were also analyzed.ResultsWe identified 95 nonsilent mutations spanning 14 genes. Specifically, TERT promoter (TERTp) mutations were exclusively detected in FTC. A total of 80% EIF1AX exon 2 mutations (4/5) and 75% TSHR mutations (3/4) occurred in FTA, whereas the rest of them occurred in FT-UMP. KRAS mutations and TP53 mutations were only presented in borderline or malignant tumors. H/N-RAS mutations were detected in all four subtypes, but were most commonly found in WDT-UMP (p = 0.031). All N-RAS mutations were located at codon 61. BRAF V600E and RET fusion were absent in the entire cohort. In FTC cases, EIF1AX mutations were all located at intron 5/exon 6 and correlated with advanced disease (p = 0.032). Both EIF1AX and TERTp mutations predicted shorter disease-free survival (p = 0.007, p = 0.024, respectively). Further analysis revealed that TERTp mutations were correlated with shorter disease-free survival in patients with minimally invasive /encapsulated angioinvasive FTC (p = 0.017), but not in those with widely invasive FTC (p = 0.297).ConclusionTERTp, EIF1AX, TSHR, H/N/K-RAS and TP53 mutations may have diagnostic or prognostic potential in follicular thyroid tumors. TERTp mutations may predict a poor outcome in patients with minimally invasive/encapsulated angioinvasive FTC.

Borderline Thyroid Tumors: a Surgeon's Perspectives

Borderline thyroid tumors are composed of hyalinizing trabecular tumor (HTT), well differentiated tumor of uncertain malignant potential (WDT-UMP), follicular tumor of uncertain malignant potential (FT-UMP) and non-invasive follicular tumor with papillary like nuclear feature (NIFTP) by World Health Organization (WHO) definition. They have different pathological feature from each other. However, it is difficult to diagnose with diagnostic imaging, fine needle aspiration (FNA) or core biopsy preoperatively. Thus, the diagnosis is usually made after diagnostic lobectomy. Main surgical concerns about borderline tumor are not performing total thyroidectomy because of relatively indolent nature of these tumors. Unfortunately, some of these tumors can be diagnosed as malignant tumor preoperatively. The other surgical concern is performing completion thyroidectomy or not after diagnostic lobectomy. Decision making is difficult even though it is generally considered that lobectomy alone is enough. In this article, we will discuss clinical features of borderline malignant tumors and surgical strategy for these tumors.

An Appraisal of Proliferation and Apoptotic Markers in Papillary Thyroid Carcinoma: An Automated Analysis

IntroductionProliferation and apoptosis are opposing processes by which the cell numbers are kept in a delicate balance, essential for tissue homeostasis, whereas uncontrolled growth of cells is a hallmark of cancer. Papillary thyroid cancer (PTC) is the commonest type of thyroid cancer, with some PTC following an indolent course, whereas the other ones are more aggressive.AimTo evaluate respective contribution of proliferation and apoptosis in the tumorigenesis of PTC by automated analysis.Materials and MethodsWe investigated the immunolabeling of phosphorylated histone H3 (pHH3), cyclin D1, active caspase-3, and bcl-2 in thirteen cases each of metastatic PTC, follicular variant of PTC (FVPTC), papillary microcarcinoma (PMC) and well differentiated tumor of uncertain malignant potential (WDT-UMP). FVPTC cases comprised seven encapsulated and six unencapsulated cases.ResultsProliferation, as assessed by pHH3 and cyclin D1 immunolabeling, was increased in all PTC variants, including the putative precursor lesion WDT-UMP, compared to normal thyroid tissue. pHH3 was immunolabeled in more cells of metastatic PTC than of PMC and of encapsulated FVPTC. Surprisingly, metastatic PTC and unencapsulated FVPTC also demonstrated more cleaved caspase-3 immunolabeled cells than the other types. In contrast, increased expression of bcl-2 protein was seen in normal thyroid areas, encapsulated FVPTC and PMC as compared to metastatic PTC. Metastatic PTC shows higher proliferation than other types of PTC but unexpectedly also higher apoptotic levels. Similar results were also seen with unencapsulated FVPTC, thus suggesting that unencapsulated FVPTC has a potential for adverse outcome. Bcl-2 was immunolabeled in a low percentage of cells in WDT-UMP.ConclusionsThe expression of the proliferative protein pHH3 together with the apoptotic marker cleaved caspase-3 may indicate an aggressive behaviour of PTC and loss of apoptosis inhibition by bcl-2 protein can further amplify the role of these proteins in tumor progression. Both cyclin D1 and bcl-2 could prove to be interesting markers of PTC precursor lesions. Automated/digital image quantification approach helps in refining the diagnostic accuracy.

Possible Roles of the Xenobiotic Transporter P-glycoproteins Encoded by the MDR1 3435 C＞T Gene Polymorphism in Differentiated Thyroid Cancers

P-glycoprotein (Pgp), encoded by the multidrug resistance 1 (MDR1) gene, is an efflux transporter which plays an important role in pharmacokinetics. The current preliminary study was designed to determine associations between a germ-line polymorphism in the MDR1 gene with differentiated thyroid carcinoma (DTC). In the current case-control study, 60 differentiated thyroid cancers (DTC)- 45 papillary TC (PTC), 9 follicular TC(FTC) and 6 well-differentiated tumors of uncertain malignant potential (WDT-UMP) were examined. Results were compared to a healthy control group (n=58) from the same population. Genomic DNA was extracted from peripheral blood with EDTA and the target gene was genotyped by real-time PCR. Carriers of the variant allele of MDR1 exon 26 polymorphism were at 2.8-fold higher risk of DTC than the control group (odds ratio [OR]: 0.3805, 95% confidence interval [Cl]: 0.1597-0.9065 (p> 0.046). Presented results suggest that the MDR1 3435TT genotype might influence risk of development of DTC and that the CC genotype might be linked to a poor prognosis. Large-scale studies are now needed to validate this association.

Encapsulated papillary thyroid carcinoma, follicular variant: A misnomer

Papillary thyroid carcinoma (PTC) has long been diagnosed based on its unique nuclear features (PTC-N); however, significant observer discrepancies have been reported in the diagnosis of encapsulated follicular patterned lesions (EnFPLs), because the threshold of PTC-N is subjective. An equivocal PTC-N may often occur in non-invasive EnFPLs and benign/malignant disagreements often create serious problems for patients' treatment. This review collects recent publications focusing on the so-called encapsulated follicular variant of papillary thyroid carcinoma (EnFVPTC) and tries to emphasize problems in the histopathological diagnosis of this spectrum of tumors, which covers encapsulated common-type PTC (EncPTC), EnFVPTC, well-differentiated tumor of uncertain malignant potential (WDT-UMP), follicular adenoma (FA) with equivocal PTC-N and minimally invasive follicular carcinoma (mFTC). We propose that EnFVPTC and other EnFPLs with equivocal PTC-N should be classified into a unified category of borderline malignancy, such as well-differentiated tumor of uncertain behavior (WDT-UB), based on their homogeneous excellent outcome. It is suggested that the unified nomenclature of these lesions may be helpful to reduce significant observer disagreements in diagnosis, because complete agreement in the diagnosis of an EncPTC, EnFVPTC or FA by all pathologists may be not possible for this problematic group of tumors. In conclusion, a malignant diagnosis of EnFVPTC should not be used to cover this spectrum of tumors until uncertainty about the nature of this lesion is settled, whether it is benign, precancerous or malignant.

Cytological features of well-differentiated tumors of uncertain malignant potential: Indeterminate cytology and WDT-UMP

The purpose of this study was to clarify the cytopathological features of well-differentiated tumors of uncertain malignant potential (WDT-UMP), a possible borderline lesion of thyroid follicular cell tumor. We analysed the cytopathological findings of fine needle aspiration (FNA) smears from 6 cases histologically diagnosed as WDT-UMP. WDT-UMP, benign and malignant lesions were compared retrospectively and morphologically. No (0%) nuclear pseudoinclusions were found in adenomatous goiter (AG), follicular adenoma (FTA) and WDT-UMP. Nuclear pseudoinclusions were increased in number in papillary thyroid carcinoma (PTC) with indeterminate cytology (0.8%) and PTC with malignant cytology (1.2%). The incidence of nuclear grooves increased gradually from AG/FTA (0%), WDT-UMP (4.5%), PTC with indeterminate cytology (6.2%) and PTC with malignant cytology (6.5%). The nuclear area of WDT-UMP, an average of 40.0 µm(2), was between that for benign AG/FTA and PTC with malignant cytology. The maximum/minimum axis of WDT-UMP (0.934) lied between that of AG/FTA and PTC. The degree of the nuclear circularity of WDT-UMP was less than that for PTC. WDT-UMP belong to indeterminate category between PTC and follicular adenoma morphologically, and this is one of the major reasons why some of PTC can be found in the indeterminate category. Questionable PTC-N including questionable nucler inclusions (artifact vacuole) may be seen in WDT-UMP, but absolute or definite nuclear inclusions with sharp border are not found in our 6 cases. Therefore this group of thyroid tumors (EnFVPTC and WDT-UMP) may be found in indeterminate category more often, because of intermediate nuclear morphology and incomplete nuclear vacuoles.

Classification of thyroid follicular cell tumors: with special reference to borderline lesions [Review

We propose a new classification of thyroid follicular cell tumors which is correlated with patient's prognosis. It is unique as to two new categories: borderline malignancy between benign and malignant, and moderately differentiated adenocarcinoma (MDA) as a differentiation classification to stratify tumor aggressiveness. As to diagnostic criteria, we recommend invasiveness (capsular and vascular invasion) to separate benign and malignant and it should not be based on presence or absence of papillary thyroid carcinoma (PTC) type nuclear features (PTC-N). Thus borderline malignancy in our new classification includes some of the formerly malignant tumors and they are 1) papillary microcarcinoma, 2) encapsulated conventional PTC (EncPTC), 3) encapsulated follicular variant PTC (EnFVPTC), 4) well differentiated tumor of uncertain malignant potential (WDT-UMP), 5) follicular tumors of uncertain malignant potential (FT-UMP), and 6) capsular invasion only follicular thyroid carcinoma (FTC). Review of the literature revealed that those thyroid tumors have consistently excellent outcome. Well differentiated follicular cell adenocarcinoma (WDA) in our classification includes common type PTC and low-risk follicular carcinoma (FTC). They are invasive (diffuse infiltrative) common type PTC and minimally invasive type FTC with less than 4 foci of angioinvasion. Moderately differentiated follicular cell adenocarcinoma (MDA) includes FTC with angioinvasion (more than 4), aggressive variants of PTC, such as tall cell, columnar cell, solid, loss of cellular polarity/cohesiveness (hobnail) variants and encapsulated carcinoma with high grade histology. Poorly differentiated carcinoma (PDC) includes PDC of WHO definition, insular carcinoma, tumors with minor anaplastic transformation and tumors with distant metastasis at presentation.

Encapsulated follicular thyroid tumor with equivocal nuclear changes, so‐called well‐differentiated tumor of uncertain malignant potential: a morphological, immunohistochemical, and molecular appraisal

There is a continuous debate regarding the classification of thyroid follicular lesions and the term "well-differentiated tumor of uncertain malignant potential (WDT-UMP)" was recently introduced to cover this problematic spectrum of tumors. The objective of this study was to reappraise WDT-UMP using morphological, immunochemical, and molecular analysis and to shed more light on encapsulated thyroid follicular-patterned tumors. A total of 30 cases of WDT-UMP with equivocal papillary thyroid carcinoma-type nuclear changes (PTC-N) or focal unequivocal PTC-N were examined. As a control, follicular adenoma (n = 29), follicular carcinoma (n = 8), hyalinizing trabecular adenoma (n = 5), and PTC (n = 48) were included. HBME-1, cytokeratin 19, and galectin-3 were positive in 12 (40.0%), 10 (33.3%) and 11 (36.7%) cases of WDT-UMP, respectively. According to the positivity of those markers, significant differences were obtained between WDT-UMP and PTC encapsulated common type (P = 0.028, 0.010, and 0.004, respectively), infiltrative follicular variant (P = 0.020, 0.026, and 0.008, respectively), and infiltrative common type (P = 0.004, 0.001, and 0.005, respectively), but not between WDT-UMP and follicular adenoma or follicular carcinoma. BRAF(V600E) mutation was absent but RET/PTC1 rearrangement was found in only two (6.7%) cases of WDT-UMP. None of the 20 patients with WDT-UMP developed recurrence, with an average follow-up of 80 months. These findings indicate that WDT-UMP has a favorable outcome and is distinct from PTC in morphological, immunohistochemical, and molecular characteristics. We propose that WDT-UMP should be classified as "well-differentiated tumor with uncertain behavior".