Radiologically occult lung cancer in the peripheral region

A rare case of radiologically occult lung cancer in the peripheral region beyond bronchoscopic visibility is reported. A 69-year-old female was referred because of positive sputum cytology. Despite detailed bronchoscopic and otorhinoralyngologic examinations, the source of malignant cells was not localized. During the follow-up period, squamous cell carcinoma of the lung periphery was detected radiologically three years after its presence was detected in sputum. Awareness of the existence of this type of cancer and careful follow-up are important in the management of patients with positive sputum cytology and no evidence of cancer.