[432] Diagnostic Utility of Immunohistochemical Profile in the Classification of Pulmonary Non-Small Cell Carcinoma in the Fine Needle Aspiration Cytology Specimen

A Zarineh, JF Silverman, YL Liu. Allegheny General Hospital, Pittsburgh, PA

Background: Fine needle aspiration (FNA) cytology is often used for the evaluation of lung cancers. The value of an accurate classification of pulmonary non-small cell carcinomas is becoming important in the era of EGFR-targeted therapies. Immunohistochemistry can be utilized in differentiating pulmonary adenocarcinoma (AC) from squamous cell carcinoma (SCCA) in resection specimens, but has not been systematically investigated in FNA specimens.
Design: Forty cases of lung FNA cytology specimens with cell blocks were retrieved from the hospital computer system. Cases consisted of 19 AC and 21 SCCA. All cases were confirmed by subsequent resection of the mass. The immunostaining for CK7, CK20, TTF-1, CK5/6, p63, and K903 was performed on cell blocks with an automated immunostainer using biotin-avidin-complex method with appropriate positive and negative controls.
Results: AC showed positivity for CK7 (78%), CK20 (26%), TTF-1 (79%), CK5/6 (0%), p63 (10%), and K903 (15%). SCCA exhibited positivity for CK7 (9%), CK20 (0%), TTF-1 (0%), CK5/6 (80%), p63 (66%), and K903 (95%).
Conclusions: CK5/6, p63 and K903 were significantly expressed in SCCA than AC, CK7 was observed in most AC and TTF-1 positivity was only seen in AC. Therefore, a panel of immunohistochemical studies including CK7, CK20, TTF-1, CK5/6, and K903 is useful in better classifying non-small cell carcinoma in FNA cytology specimens.
Category: Cytopathology

Wednesday, March 11, 2009 1:00 PM

Poster Session VI # 47, Wednesday Afternoon