In one case, we did not have a morphological suspicion of neuroendocrine morphology and, without performing respective immunohistochemical analysis, we made the diagnosis of a NSCLC NOS, but archival immunohistochemistry revealed an extensive expression of synaptophysin and chromogranin, leading to the diagnosis of a LCNEC (Figure 4D,E). The gene discussed is SYP; the disease is non-small cell lung carcinoma.