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Salajegheh A, Petcu EB, Smith RA, Lam AKFollicular variant of papillary thyroid carcinoma: a diagnostic challenge for clinicians and pathologists. Postgrad Med J 84(988): 78-82

Department of Pathology, Griffith Medical School, Gold Coast Campus, Gold Coast, Queensland 4222, Australia.
Postgraduate medical journal (Impact Factor: 1.45). 03/2008; 84(988):78-82. DOI: 10.1136/pgmj.2007.064881
Source: PubMed

ABSTRACT

The follicular variant of papillary thyroid carcinoma (FVPTC) presents a type of papillary thyroid cancer that has created continuous diagnosis and treatment controversies among clinicians and pathologists. In this review, we describe the nomenclature, the clinical features, diagnostic problems and the molecular biology of FVPTC. It is important for clinicians to understand this entity as the diagnosis and management of this group of patient may be different from other patients with conventional PTC. The literature suggests that FVPTC behaves in a way similar, clinically, to conventional papillary thyroid carcinoma. However, there are some genotypic differences which may characterise this neoplasm. These parameters may account for the phenotypic variation described by some scientists in this type of cancer. Further understanding can only be achieved by defining strict pathological criteria, in-depth study of the molecular biology and long term follow-up of the optional patients with FVPTC.

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    • "Our study has also shown association between FVPTC and distant metastasis when compared with the classical subtype. Therefore, inactivation of PTEN in this particular subtype of PTC could probably have several clinical implications as other studies have revealed the diagnostic and clinical challenges associated with FVPTC as its molecular features are shared by both papillary thyroid cancers and follicular neoplasms (Salajegheh et al, 2008; D et al, 2014). "
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    ABSTRACT: PTEN gene at chromosomes 10q23.3 is a tumour suppressor gene that is inactivated in many types of human cancers. The known mechanisms of PTEN inactivation are rendered to mutation, epigenetic silencing by aberrant methylation or gene deletion. Although PTEN role has been documented in many cancers, PTEN alteration in papillary thyroid carcinoma (PTC) has not been fully elucidated. The aim of this study is to comprehensively investigate PTEN alterations in a large cohort of Middle Eastern papillary thyroid cancer by immunohistochemistry and fluorescent in situ hybridisation (FISH). PTEN protein expression was analysed by immunohistochemistry in a tissue microarray (TMA) format in a large cohort of more than 1000 patients with papillary thyroid cancer. Copy number changes in PTEN were analysed by FISH and data were correlated with clinicopathological parameters along with survival analysis. PTEN inactivation reflected by complete absence of staining was seen in 24.5% of PTC samples, whereas PTEN deletion was seen only in 4.8% of the tested samples by FISH. No association was seen between PTEN loss of protein expression and PTEN gene deletion. However, interestingly, PTEN loss of expression was significantly associated with the follicular variant subset of papillary thyroid cancer. Our study confirmed that PTEN might have a role in pathogenesis in a subset of PTC. PTEN loss of protein expression is a more common event in follicular variant of papillary thyroid cancer. Lack of association between PTEN loss of protein expression and PTEN gene deletion might indicate that gene deletion may not be the sole cause for PTEN loss of expression and these results might raise the possibility of other mechanism such as promoter methylation-mediated gene silencing to be responsible for PTEN inactivation.British Journal of Cancer advance online publication, 19 May 2015; doi:10.1038/bjc.2015.169 www.bjcancer.com.
    Full-text · Article · May 2015 · British Journal of Cancer
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    • "Therefore the tumor should be designated FVPTC. Chen and Rosai stressed the importance of nuclear rather than architectural pattern in making a diagnosis of PTC and showed that FVPTC behaved similarly to the conventional PTC[9]. Because of the follicular pattern it was often confused with other benign and neoplastic follicular lesions including adenomatoid nodule , follicular adenoma and follicular carcinoma[10,11]. "
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    ABSTRACT: Background: Fine needle aspiration cytology (FNAC) is an important investigation in preoperative diagnosis of thyroid lesions. Follicular variant of papillary carcinoma thyroid (FVPTC) is a well defined entity in histopathology, but its diagnosis in FNAC is usually missed and is challenging compared to classic papillary thyroid carcinoma. Aims: The purpose of this study is to retrospectively analyze cytological features in histologically confirmed cases of FVPTC, compare them with literature and document the features that could increase the sensitivity of FNAC diagnosis. Materials and Methods: Cytological smears from 22 histologically confirmed cases of FVPTC were evaluated for microscopic pattern and nuclear features by two independent pathologists and results compared with previous studies. Statistical analysis was done based on bivariate Pearson's correlation coefficient. Results: Among 22 cases 21 were female and one male with age range 21 - 50 years. All patients had a solitary nodule except one with multicentric presentation. Preoperative cytological diagnosis were, classic papillary thyroid carcinoma (PTC); 7, FVPTC; 3, suspicious for PTC; 4, follicular neoplasm; 5 and adenomatous goiter;3. Diagnosis upon cytological review were, FVPTC; 11, classic PTC; 7 , suspicious for PTC; 2, follicular adenoma;1 and adenomatous goiter; 1. Conclusion: We conclude that cellular smears with features as observed in our case like microfollicular pattern, syncytial clusters, fine powdery chromatin, anisonucleosis and nucleomegaly should alert the pathologist to look carefully for other more specific features like nuclear grooves and nuclear pseudoinclusions. This approach will help in avoiding misdiagnosis of FVPTC and would aid in choosing the right treatment modality.
    Full-text · Article · Mar 2014
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    • "Follicular variant of papillary thyroid carcinoma (FVPTC) is the third most common type of PTC, following conventional papillary thyroid carcinoma (CPTC) and papillary microcarcinoma [2]. Patients with FVPTC often present with larger tumor size and at a younger age than patients with CPTC [3]. FVPTC also shows less ☆ Disclosure/conflict of interest: The authors wish to state that they have no conflicts of interest or disclosures to make. "
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    ABSTRACT: Mutation of the BRAF gene is common in thyroid cancer. Follicular variant of papillary thyroid carcinoma is a variant of papillary thyroid carcinoma that has created continuous diagnostic controversies among pathologists. The aims of this study are to (1) investigate whether follicular variant of papillary thyroid carcinoma has a different pattern of BRAF mutation than conventional papillary thyroid carcinoma in a large cohort of patients with typical features of follicular variant of papillary thyroid carcinoma and (2) to study the relationship of clinicopathological features of papillary thyroid carcinomas with BRAF mutation. Tissue blocks from 76 patients with diagnostic features of papillary thyroid carcinomas (40 with conventional type and 36 with follicular variant) were included in the study. From these, DNA was extracted and BRAF V600E mutations were detected by polymerase chain reaction followed by restriction enzyme digestion and sequencing of exon 15. Analysis of the data indicated that BRAF V600E mutation is significantly more common in conventional papillary thyroid carcinoma (58% versus 31%, P = .022). Furthermore, the mutation was often noted in female patients (P = .017), in high-stage cancers (P = .034), and in tumors with mild lymphocytic thyroiditis (P = .006). We concluded that follicular variant of papillary thyroid carcinoma differs from conventional papillary thyroid carcinoma in the rate of BRAF mutation. The results of this study add further information indicating that mutations in BRAF play a role in thyroid cancer development and progression.
    Full-text · Article · Dec 2010 · Human pathology
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