Since its introduction some twenty years ago the Papanicolaou technique for cervical-vaginal cytology has had a tremendous impact on the detection of precancerous lesions and in situ cancer in the female genital tract. It has forced the clinician and pathologist to study the early lesions of cancer, particularly in the female genital tract and has brought about a better understanding of their biology. Cytology has over the years been extended to other areas, particularly the respiratory tract. Two recent areas of emphasis are the thin-needle aspiration biopsy and direct brushing of mucosal surfaces through the various fiber optic scopes now available, particularly for the respiratory and gastrointestinal tract
