INSM1 and neoplasm: Moreover, although Br-NENs are currently described as neoplasms with a morphology and immunophenotype (CgA SYN, INSM1, etc.)similar to that of gastroenteropancreatic and pulmonary NENs, the nuclear features typically seen in extra-mammary organs (“salt and pepper” stippled chromatin and small nucleoli) are not frequently noted in Br-NENs [4, 16].