Clinical Features of Pulmonary Large Cell Neuroendocrine Carcinoma

Purpose: This study was performed to investigate the clinical features of large cell neuroendocrine carcinomas (LCNEC).

Materials and methods: 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.

Results: 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.

Conclusion: 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.