Regard to neuroendocrine markers (Fig. 5), the NEC component exhibited focal reactivity toward chromogranin A (15% of neoplastic cells) and synaptophysin (31% of neoplastic cells), while CD56, insulinoma-associated protein 1 (INSM1), and ISL LIM homeobox 1 (ISL1) showed general positivity. Here, ISL1 is linked to neuroendocrine carcinoma.