Tall cell variant of papillary thyroid carcinoma without extrathyroid extension: biologic behavior and clinical implications.

Background: 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.

Poorly differentiated thyroid carcinomas defined on the basis of mitosis and necrosis: a clinicopathologic study of 58 patients.

Background: Poorly differentiated thyroid carcinomas (PDTC) occupy an intermediate position at the prognostic level on the spectrum of thyroid carcinoma progression. However, their histologic definition is controversial. The objective of the current study was to assess the prognostic significance of PDTC defined on the basis of mitosis and necrosis and search for prognostic markers within this group of tumors that are predictive of overall survival (OS) and progression-free survival (PFS).