CHGA and rectum neuroendocrine neoplasm: The most common immunohistochemical markers for neuroendocrine neoplasms are synaptophisine, chromogranin A, and neuro-specific enolase [25], but the most sensitive marker for rectal NETs is SATB2, which is positive in 88% of rectal NETs, and its positivity confirms a rectal origin in case of metastasis of occult origin [26].