Between 1971 and 1992, 55 patients with grade 1 (G1) (n = 32) or grade 2 (G2) (n = 23) neuroendocrine bronchial carcinomas (males: 26, females: 29; mean age: 47.7 years, range: 13-77 years) were treated. The sexes were evenly distributed in the two groups. Patients with G1 were significantly younger than those with G2 tumors (43.3 vs 53.7 years; P < 0.05). There were no statistically significant differences between G1 and G2 concerning peripheral or central localization, laterality or maximum tumor diameters. Patients with G1 had a higher incidence of tumor-related symptoms and a longer mean duration of these symptoms (21.8 months) than G2 cases (14 months) but the differences were not statistically significant either. No case displayed any symptoms of hormonal activity. Fifty-two patients underwent resection, one was non-resectable for anatomical, and one for functional, reasons; a third refused an operation. We performed 8 pneumonectomies, 36 lobectomies (8 by using bronchoplasty), 2 bronchotomies and 6 segmental resections. Twelve G2 cases had N1 or N2 lymph node metastases, two intrapulmonary metastases were removed. After a median observation time of 55.7 months the 10-year survival rate for the total collective is 90.6%. For G1 it is 100%, compared with 76.4% for G2 patients, 3 of whom died of the tumor (P < 0.05; significant). In univariate analysis: age over 48 years, lymphatic invasion, and lymph node metastasis were also significantly correlated with a poor survival rate. Multivariate analysis proved lymphatic permeation to be the only independent prognostic factor (the survival rate was 100% where there was no invasion, but only 74% where this had occurred). Smolle-Jüttner, Popper, Klemen, Pinter, Pongratz-Roeger, Smolle, Friehs, , (1993). Clinical features and therapy of "typical" and "atypical" bronchial carcinoid tumors (grade 1 and grade 2 neuroendocrine carcinoma). European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery, 1993 ;7(3):121-4; discussion 125. https://www.ncbi.nlm.nih.gov/pubmed/8384862