The cancerization field concept implies that lung cancer multicentricity may be a frequent event and primary studies using white-light bronchoscopy (WLB) have reported a high prevalence of multicentricity in patients with roentgenographically occult lung cancer. We have used autofluorescence bronchoscopy (AFB) to reassess the prevalence of synchronous lesions in patients referred for the staging and/or treatment of occult lesions initially detected during WLB. All the patients referred with high-grade preinvasive lesions (severe dysplasia, DYS S and carcinoma in situ, CIS) and occult invasive squamous cell carcinoma (CIV) of the bronchus initially detected during WLB at other centers, underwent AFB. Data were prospectively collected and retrospectively analyzed to assess the prevalence of synchronous occult lesions. From January 1996 to December 2001, 28 patients (26 males, 2 females; mean age: 65 +/- 11) were assessed. After re-evaluation, in two cases, the referred lesions corresponded only to metaplasia and were discarded from analysis. The 26 other patients were referred for 28 lesions (3 DYS S, 19 CIS and 6 CIV; 2 patients were referred with two synchronous lesions). AFB revealed, in these 26 patients, six additional lesions (1 DYS S, 4 CIS and 1 CIV). Multicentricity in this group, initially estimated to amount to 7% with WLB alone, raised to 23% by using AFB. The high prevalence of synchronous lesions in this series of patients with occult DYS S, CIS and occult CIV suggests that AFB may be a useful adjunct in the pretreatment evaluation.