The identification of atypical reserve cells in smears of patients with premalignant and malignant changes in the squamous and glandular epithelium of the uterine cervix.

Atypical reserve cells can be recognized in cervical smears by their characteristic exfoliation pattern and the fragility of their cytoplasm. The frequency of cases with such cells in 30,000 cervical smears is given, as well as that in 440 cases of dysplasia, epidermoid carcinoma in situ and invasive carcinoma. The presence of atypical reserve cells was found to increase in frequency with the increasing severity of the lesions. The bipotential character of these cells is discussed in relation to the possible progression to carcinoma in situ of the adenomatous type in two of the 42 cases of pure atypical reserve cell hyperplasia, and the presence of these cells in the majority of the 43 cases of adenocarcinoma of the uterine cervix in the present series.