Poorly differentiated carcinomas of the thyroid with trabecular, insular, and solid patterns

Abstract

BACKGROUNDThe term poorly differentiated (PD) carcinoma was proposed 20 years ago to define aggressive, follicular‐derived thyroid carcinomas with behavior intermediate between follicular/papillary and anaplastic carcinomas. Among the variable histologic patterns recognized in such tumors, trabecular‐insular‐solid (TIS) areas usually are predominant. Conversely, some authors pointed out that PD carcinomas are characterized by unequivocal, high‐grade histology with atypias, high mitotic counts, and necrosis rather than by a specific growth pattern.METHODSThe clinicopathologic features of a series of 183 thyroid carcinomas with predominant (n = 165 tumors) or focal (n = 18 tumors) TIS growth patterns were studied by univariate and multivariate overall survival analyses and were compared with clinical outcomes. Subgroups included tumors with predominant oxyphilic features (n = 66 tumors) and (residual) papillary carcinoma features (n = 24 tumors). Control groups of papillary (n = 68 tumors), follicular (n = 71 tumors), and anaplastic (n = 35 tumors) carcinomas also were included for overall survival analysis.RESULTSTIS carcinomas had an intermediate behavior between papillary/follicular and anaplastic carcinomas (P < 0.0001). Univariate and multivariate statistical analyses demonstrated that age > 45 years (P = 0.007), the presence of necrosis (P < 0.0001), and a mitotic count > 3 per 10 high‐power fields (P = 0.01) were associated with poor outcome. A simplified scoring system based on statistically significant parameters allowed the identification of three prognostic subgroups (P < 0.0001).CONCLUSIONSPD TIS carcinomas overall followed a more aggressive course compared with differentiated thyroid carcinomas, irrespective of the extent of the TIS component. However, a numeric scoring system applied to specific clinicopathologic parameters further may identify three prognostic categories of patients who have significantly different survival rates at 5 years and 10 years. Cancer 2004;100:950–7. © 2004 American Cancer Society.

Histologic coagulative tumour necrosis as a prognostic indicator of aggressiveness in renal, lung, thyroid and colorectal carcinomas: A brief review

“…Within this group of patients, microstaging (tumour size, the extent of capsular invasion, and extrathyroid extension), rather than growth pattern or cell type, is capable of stratifying patients into various prognostic categories (6). These findings indicate that grading of thyroid carcinoma based on increased mitotic activity, necrosis, nuclear pleomorphism and invasiveness is of high clinical and prognostic significance, whereas architectural grading has not yet been clearly proven to have any prognostic value (6)(7)(8)(9)11,18,19).…”

Histopathologic characterization of radioactive iodine‐refractory fluorodeoxyglucose‐positron emission tomography‐positive thyroid carcinoma

“…2 Some authors have advocated using architectural features such as a solid/trabecular growth pattern (as advocated by Japanese pathologists), whereas others propose using a proliferate grading system (ie, nuclear atypia, mitoses, and necrosis) to establish the diagnosis of PDTC. [3][4][5][6] Recently, an international group of pathologists convened in Turin, Italy and proposed new consensus diagnostic criteria for PDTC. These authors require the presence of 1) a solid/trabecular/ insular growth pattern; 2) the absence of the nuclear features of papillary thyroid carcinoma (PTC); and 3) the presence of at least 1 of the following features: convoluted nuclei, high mitotic activity, and tumor necrosis.…”

Submucosal Esophageal Metastasis in a Patient with Poorly Differentiated Thyroid Carcinoma: a Case Report

“…The histologic and cytologic aspects are detailed with a focus on key features helpful in the diagnosis of PDTC, both using surgical pathologic examinations and in cytology-based studies (2). PDTC exhibits intermediate behaviors between well-differentiated thyroid carcinoma and anaplastic thyroid carcinoma (1,(3)(4)(5)(6).…”