Poorly differentiated follicular thyroid carcinoma with rhabdoid phenotype: A clinicopathologic, immunohistochemical and electron microscopic study of two cases

Jorge Albores-Saavedra, Suash Sharma

Research output: Contribution to journalArticle

26 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)98-104
Number of pages7
JournalModern Pathology
Issue number2
StatePublished - Jan 1 2001



  • Immunohistochemistry
  • Poorly differentiated follicular carcinoma
  • Rhabdoid phenotype

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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