High survival rate of 6 cases of pulmonary large cell neuroendocrine carcinoma formerly classified as small cell carcinoma.

Abstract

In the revised WHO classification of lung cancer, published in 1999, large cell neuroendocrine carcinoma (LCNEC) was employed as a new histological entity. LCNEC is generally considered a high-grade malignant lung cancer, and appropriate treatment remains to be determined. Before its new classification, LCNEC had long been classified into several entities. Advancing the review of previous cases in Nippon Medical School Hospital, we noticed that some LCNEC patients were formally diagnosed as having small cell lung cancer (SCLC), and they showed long-term survival. All histological specimens of surgically resected SCLC in Nippon Medical School Hospital were reclassified according to the 1999 WHO classification manual. Their neuroendocrine differentiations were confirmed by the use of immunostainings with chromogranin A and synaptophysin. Fourteen cases satisfied the qualifications for both histological and clinical reevaluation. Among them, 6 patients were reclassified as LCNEC, and their stage distribution was as follow: IA; 1, IB; 2, IIIA; 2, and IIIB; 1. Their survival term ranged from 33.8 to 78.0 months; 5 were still alive, and 1 (IIIB) died 57.6 months after surgery. According to this study, all the LCNEC patients who were treated as SCLC patients showed more favorable prognoses than patients described in published studies, even overall lung cancer. Therefore, it is suggested that multimodality therapy for SCLC may improve the prognoses of patients with LCNEC.