Because of the difficult diagnosis in biopsies or cytology specimens, LCNEC may be suspected when the tumor shows non-small cells, high-grade neuroendocrine features with no overt squamous or glandular differentiation and expresses more than one neuroendocrine marker (synaptophysin, chromogranin, and/or CD56) (16). This evidence concerns the gene SYP and large cell neuroendocrine carcinoma.