Poorly Differentiated Follicular Thyroid Carcinoma with Rhabdoid Phenotype: A Clinicopathologic, Immunohistochemical and Electron Microscopic Study of Two Cases

Abstract

Poorly differentiated thyroid carcinomas with follicular cell phenotype are not well defined. Different diagnostic criteria have been employed for these tumors, including solid growth, nodular, trabecular, and insular patterns. Cytologic features, such as a predominance of tall and columnar cells, have been considered to be diagnostic of poorly differentiated carcinoma. However, there is no agreement among surgical pathologists regarding morphologic criteria for poorly differentiated thyroid carcinoma. We report two unique thyroid neoplasms that we interpreted as poorly differentiated follicular carcinomas. Nodular, trabecular, and sheetlike patterns predominated in both tumors. They were composed of cells that were focally immunoreactive for thyroglobulin and had large vesicular nuclei with prominent nucleoli. A variable number of cells showed rhabdoid phenotype. The rhabdoid inclusions did not stain for thyroglobulin but contained whorls of intermediate filaments that were vimentin positive. There were foci of necrosis and numerous mitotic figures. Both patients were adults and died with multiple pulmonary metastases. The presence of rhabdoid cells in poorly differentiated follicular carcinomas broadens the spectrum of tumors with rhabdoid phenotype. More cases are needed to determine whether the rhabdoid phenotype is a marker for poorly differentiated follicular carcinoma as well as an independent adverse prognostic factor.

Rhabdoides Meningeom

“…Auch Karzinome können eine rhabdoide Morphologie aufweisen, wie an Beispielen von Karzinomen des Zökums [6], des Magens [23] und der Schilddrü-se [1] gezeigt wurde. Der Nachweis von Keratinen, insbesondere ein diffus-zytoplasmatisches oder membranständiges Anfärbungsmuster würden differenzialdiagnostisch eher für eine Metastase eines Karzinoms sprechen.…”

A Rare and Particular form of Goiter to Recognize

“…In this case, although autoimmune thyroiditis was suspected clinically, the lack of a lymphocytic infiltrate made autoimmune thyroiditis very unlikely (14).…”

“…Irregularities at the edge of the nodules can simulate capsular invasion (1,5,6,13). The histology is thought to vary depending on site of enzymatic block (5,6,14).…”

“…This is due to the fact that the morphologic criteria employed to define undifferentiated thyroid carcinoma in most publications have been trabecular, solid, insular, cribriform growth patterns which can be seen in dyshormonogenetic goiters. But strict histologic criteria will help separate these lesions (1,5,6,(14)(15)(16)(17).…”

Poorly differentiated thyroid carcinoma with rhabdoid phenotype: A diagnostic dilemma—Report of a rare case

“…Since then, this aggressive neoplasm has been recognized as a phenotypic expression of many neoplasms [4][5][6][7] occurring in various extrarenal sites. Subsequently, eight cases of thyroid neoplasms with rhabdoid morphology have been reported in the literature [5][6][7][8][9][10][11][12], which include cases of poorly differentiated follicular carcinoma [5][6][7][8]10] and anaplastic carcinoma [9,11,12] of thyroid with rhabdoid phenotype. In the cases reported by Sumida et al [9] and Sato et al [12] the rhabdoid tumor was a component of anaplastic carcinoma, which apparently transformed from papillary thyroid carcinoma.…”