Clinical implication of atypical cells from sputum in patients without lung cancer

Atypical-but not definitely malignant-cells in cytological examinations of sputum are usually associated with lung cancers. However, atypical cells are occasionally identified in patients without lung cancer. The aim of this study was to determine the clinical implication of the atypical cells from sputum in patients without lung cancer or other malignancies.

All patients with atypical cells observed following cytological examination of sputum on one or more occasion over a 2-year period in Seoul National University Hospital were enrolled. After exclusion of patients followed up for less than 6 months, their clinical data were reviewed retrospectively.

Among 601 enrolled patients with atypical cells, lung cancers were diagnosed within 30 days of identification of atypical cells in 542 (90.2%) patients. Five out of 59 patients who had no evidence of lung cancer, were subsequently diagnosed with lung cancer or other malignancies following a mean observation of 164 days. In the other 54 patients without subsequent malignancies, the most common respiratory diseases were pneumonia including tuberculosis.

The subsequent development of malignancy in patients with atypical cells in sputum despite a thorough evaluation was rare, and close observation without invasive diagnostic procedures might be simply required in these patients.