Tall cell variant of papillary thyroid carcinoma without extrathyroid extension: Biologic behavior and clinical implications
ABSTRACT The tall cell variant (TCV) is a histologic subtype of papillary thyroid carcinoma (PTC) that is more aggressive than "classical" PTC. Most authors believe that TCV's worse prognosis is related to older age at presentation, larger tumor size, and high frequency of extrathyroid tumor extension (ETE). To assess the biologic and clinical behavior of TCV without ETE, we performed a detailed comparative clinicopathologic analysis of classical PTC and TCV without ETE.
TCV was defined as a PTC harboring >50% tall cells, while classical PTC was restricted to those tumors containing >1% papillae and <30% tall cells. Microscopic analysis and chart review identified 62 cases of TCV and 83 classical PTC without ETE. These patients were analyzed for various pathologic, imaging, and clinical parameters including outcome.
There was no statistical difference between TCV and classical PTC in relation to age, gender, tumor size, risk stratification, type of therapy, and length of follow-up. TCV displayed more invasion of the tumor capsule and more often infiltrated into the thyroid capsule (p = 0.047 and 0.0004, respectively). Among patients with microscopically assessable regional lymph node (LN), 33 of 49 (67.3%) patients with TCV had LN metastasis at presentation, while only 24 of 60 (40%) classical PTC had positive nodes (p = 0.004). In multivariate analysis, histologic subtype (TCV vs. classical PTC) was the only independent factor associated with LN metastases (p = 0.007). In patients with adequate follow-up, 4 of 62 (6.5%) classical PTC and 7 of the 47 (14.9%) TCV had thyroid cancer recurrence (p = 0.202). TCV recurred at a distant site (3 of 47, 6.4%) while none of the 62 classical PTC developed distant metastases (p = 0.077).
TCV without ETE is biologically a more aggressive tumor than classical PTC without ETE independent of age, gender, and tumor size.
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ABSTRACT: Background: The tall cell variant of papillary thyroid cancer (TCV) is an aggressive variant of papillary thyroid cancer (PTC) that is believed to have worse outcomes than classical PTC. The objective of this study was to investigate the incidence, survival and disease recurrence of patients with TCV and compare them with other PTC in a whole population. Methods: Information on all thyroid carcinomas diagnosed in Iceland from 1990 to 2009 was obtained from the Icelandic Cancer Registry. PTC diagnosed post mortem was excluded. The date of diagnosis, sex and age at diagnosis was registered. All histopathology material was re-evaluated and papillary thyroid tumors classified as either TCV or other types of PTC. Tumors were classified as TCV if more than 50% of cells were tall (height > twice the width). TNM-stage was determined for all the cases. Endpoints were thyroid cancer specific death and thyroid cancer recurrence. Results: Out of 376 patients diagnosed with PTC in the study period, 49 (13%) were classified as TCV. Patients with TCV were older (66 years vs. 49 years, p<0.001), more often had pT4 tumors (71% vs. 15%, p<0.001), had higher rates of nodal metastasis (51% vs. 22%, p<0.001) and more often distant metastasis (14% vs. 2%, p<0.001). The age adjusted incidence of TCV for men was 0.5/100,000 (95% CI: 0.3-0.7) and for women 0.7/100,000 (95% CI: 0.4-1.0) between 1990-2009. The 5-year disease specific survival for TCV was 83% (95% CI 68-91) compared to 98% (95% CI: 96-99) for other PTC respectively (p<0.001). In multivariate analysis, TCV histology was an independent risk factor for recurrence (HR : 3.18, 95% CI 1.48-6.84) but not for disease specific survival (HR: 1.86, 95% CI 0.77-4.73). Conclusions: TCV comprises 13% of all diagnosed PTC in Iceland with an incidence of 0.5/100,000 for men and 0.7/100,000 for women. Patients diagnosed with TCV have worse 5-year disease specific survival than patients with other PTC. TCV histology is an independent risk factor for disease recurrence but not for disease specific survival.Thyroid: official journal of the American Thyroid Association 10/2014; DOI:10.1089/thy.2014.0075 · 2.60 Impact Factor
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ABSTRACT: Follicular cell-derived carcinomas of the thyroid gland comprise a heterogeneous group of malignant neoplasms of the thyroid gland with varied histologic appearance and molecular profiles. In most patients, these tumors represent relatively indolent neoplasms; however, certain subtypes/variants behave in an aggressive manner, and the recognition of this subset of tumors is essential because of their variable response to therapy and significant morbidity and mortality. Fine-needle aspiration is considered an essential tool for the diagnosis of suspicious thyroid nodules. In this review, the authors discuss the clinical, histologic, and molecular findings and the prognostic implications of aggressive thyroid neoplasms with emphasis on the characteristic cytomorphologic features on fine-needle aspiration smears. Cancer (Cancer Cytopathol) 2014. © 2014 American Cancer Society.Cancer Cytopathology 07/2014; 122(7). DOI:10.1002/cncy.21417 · 4.43 Impact Factor
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ABSTRACT: BackgroundThe tall cell variant of papillary thyroid carcinoma (TCVPTC) is more aggressive than classic papillary thyroid carcinoma (PTC), but the percentage of tall cells needed to diagnose TCVPTC remains controversial. In addition, little is known about the clinicopathologic features of classic PTC with tall cell features (TCF).MethodsWe retrospectively selected and reviewed the clinicopathologic features and presence of the BRAF mutation in 203 cases of classic PTC, 149 cases of classic PTC with TCF, and 95 cases of TCVPTCs, which were defined as PTCs having <10%, 10-50%, and ≥50% tall cells, respectively.ResultsTCVPTCs and classic PTCs with TCF did not vary significantly in clinicopathologic characteristics such as pathologic (p) T stage, extrathyroidal extension, pN stage, lateral lymph node metastasis, or BRAF mutations; however, these features differed significantly in TCVPTCs and classic PTCs with TCF in comparison to classic PTCs. Similar results were obtained in a subanalysis of patients with microcarcinomas (≤1.0 cm in size).ConclusionsClassic PTCs with TCF showed a similar BRAF mutation rate and clinicopathologic features to TCVPTCs, but more aggressive characteristics than classic PTCs.The Korean Journal of Pathology 06/2014; 48(3):201-8. DOI:10.4132/KoreanJPathol.2014.48.3.201 · 0.17 Impact FactorThis article is viewable in ResearchGate's enriched formatRG Format enables you to read in context with side-by-side figures, citations, and feedback from experts in your field.