Accuracy of blind cytologic diagnosis of diploid breast cancer.

Fifteen fibroadenomas and 20 adenocarcinomas with identical diploid DNA histogram patterns were blindly diagnosed in fine needle aspirates by 22 cytopathologists. Despite the total lack of clinical information, each cytopathologist, on the average, managed to correctly diagnose 33 of the 35 cases. There were more false diagnoses among the fibroadenomas than among the cancers.