Anaplastic thyroid carcinoma: morphologic findings and PAX-8 expression in cytology specimens.
OBJECTIVE
To evaluate the morphologic findings most encountered in anaplastic thyroid carcinomas (ATCs) and evaluate for the expression of PAX-8.


METHODS
The cytology specimens from 21 cases of ATC were evaluated for the following several cytologic criteria: cell morphology, pleomorphism, presence or absence of multinucleated cells, colloid, neutrophilic infiltrate and well-differentiated component. Immunohistochemical studies for PAX-8 were performed on cell blocks in selected cases.


RESULTS
The most common morphology present was epithelioid, followed by spindle, multinucleated giant cell and rhabdoid, with 75% demonstrating more than 1 cell morphology. Marked pleomorphism (81%), neutrophilic infiltrate (90%) and necrosis (63%) were frequent. No nuclear grooves, colloid or well-differentiated component was identified in any case. Immunocytochemical stains for PAX-8 were negative in 5 cases in which a cell block was available.


CONCLUSIONS
ATC is a tumor with diverse morphologic characteristics, and more than 1 cell morphology is usually present. A neutrophilic infiltrate is a common finding and represents a clue to the correct diagnosis.
Rivera
Michael
M
Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA.
Sang
Cristina
C
Gerhard
Rene
R
Ghossein
Ronald
R
Lin
Oscar
O
D000368:Aged; D044963:Biopsy, Fine-Needle; D002277:Carcinoma / Q000378:metabolism* / Q000473:pathology*; D003581:Cytodiagnosis; D003937:Diagnosis, Differential; D005260:Female; D015726:Giant Cells / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D000072636:PAX8 Transcription Factor; D051761:Paired Box Transcription Factors / Q000378:metabolism*; D013964:Thyroid Neoplasms / Q000378:metabolism* / Q000473:pathology*
D000072636:PAX8 Transcription Factor; C083325:PAX8 protein, human; D051761:Paired Box Transcription Factors