Which marker is included in the IHC panel for primary adrenal cortical tissue?

• A. PTH
• B. SF-1
• C. SALL4
• D. chromogranin

Answer: (B)

SF-1, or steroidogenic factor-1, is a nuclear transcription factor essential for the development and function of steroid-producing tissues, including the adrenal cortex. In immunohistochemistry, SF-1 reliably stains adrenocortical cells and adrenocortical tumors, making it a go-to marker to confirm adrenal cortical origin when the tissue source of a tumor is in question.

PTH would indicate parathyroid tissue rather than adrenal cortex. SALL4 marks germ cell–origin tumors and isn’t expressed in the adrenal cortex. Chromogranin A marks neuroendocrine cells and is typically positive in pheochromocytoma (adrenal medulla) or other neuroendocrine neoplasms, not in adrenal cortical tissue.

Thus SF-1 is the best marker to identify primary adrenal cortical tissue.