Contribution of immunocytochemistry in routine diagnostic cytology

The authors report the experience of applying immunocytochemistry in routine cytological examination and its contribution for diagnosis during a period of 3 yr in Veterans General Hospital-Taipei, Taiwan. From August 1991 to July 1994, the cytology laboratory received 5,762 non-gynecologic specimens with urine excluded. Immunocytochemistry was performed selectively in problematic cases. A total of 215 stainings including 124 epithelial markers, 50 lymphoma/leukemia markers, 22 neuroglial and choroid plexus markers, seven mesenchymal markers, six melanoma markers, and six others was performed on 145 specimens consisting of 89 effusions, 28 fine-needle aspirations, 11 cerebrospinal fluids, and 17 other specimens. Effusions were by far the most frequent specimens for immunocytochemistry and the epithelial markers were the most frequently used antibodies. The immunocytochemical results were essential in 41 specimens (28%), confirmatory in 37 (26%), and non-contributory in 67 (46%). Essential and confirmatory results occurred in 49% of effusions (44/89), 71% of fine-needle aspirations (20/28), 55% of cerebrospinal fluids (6/11), and 47% of other specimens (8/17). It is concluded that immunocytochemistry is proved to be a good aid for the final diagnosis of daily cytologic practices in which the fine-needle aspiration specimens are benefitted best.