Combined large cell neuroendocrine carcinoma and adenocarcinoma with epidermal growth factor receptor mutation in a female patient who never smoked.

A female patient in her sixties, who had never smoked, was found to have a 5-mm nodule in a computed tomography (CT) scan. The follow-up CT scan after 19 months showed that the nodule had grown to 26 mm. We performed a left upper lobectomy. Pathological examination revealed a combined large cell neuroendocrine carcinoma (LCNEC) and adenocarcinoma with components of large cell carcinoma and bronchioloalveolar carcinoma (BAC). Tumor cells were separately collected from components of both the LCNEC and adenocarcinoma, and a mutational analysis of the epidermal growth factor receptor (EGFR) gene demonstrated that both components had the same L861Q mutation at exon 21. We assume that the LCNEC originated from the adenocarcinoma based on the fact that the patient was a non-smoking female, the tumor was located in the periphery, the tumor had a BAC component, and the same EGFR mutation was found in both the LCNEC and adenocarcinoma components.