Clinical Features of Pulmonary Large Cell Neuroendocrine Carcinoma

This study was performed to investigate the clinical features of large cell neuroendocrine carcinomas (LCNEC). We retrospectively reviewed the histopathology and clinical information of 37 patients with LCNEC, diagnosed between June 1992 and May 2002 at the Severance Hospital, and performed immunohistochemical (IHC) staining. The prevalence of LCNEC among primary lung cancers was 0.3%, 37 out of 13, 012 cases over a 10 year period. The mean age was 61+/-12 years old, with 34 (92%) males and 3 (8%) females. 30 patients smoked, with an average of 42 packs per year. A cough was the most frequent symptom. The tumor was located at the periphery of the lung in 24 cases (65%). Among the 30 cases that underwent surgery, 4 were diagnosed pathological stage IA, 11 IB, 1 IIB, 13 IIIA and 1 IIIB. The 7 clinically non-operable cases were IIIB in 3, and IV in 4. The positive rates of CD56, thyroid transcription factor-1 (TTF-1), chromogranin A, synaptophysin and 34betaE12 for tumor cells were 88.9, 55.6, 42.1, 31.6 and 21.1%, respectively, from the IHC staining. The median survival time and 5 year-survival rate were 24 months and 27%, respectively. The group that underwent surgery had a better prognosis than those that did not. The positive rates for the tumor markers varied, but those of the CD56 and TFT-1 were the highest. The possibility of LCNEC needs to be evaluated for the following situations: small cell carcinomas located at the periphery and not responding chemotherapy, small cell carcinomas diagnosed by percutaneous needle aspiration, poorly differentiated non-mall cell carcinomas, with uncertain histologic type, and unclassified neuroendocrine tumor, etc.