Small, well-differentiated neuroendocrine tumors can cause severe hypercortisolism, yet remain undetectable on DOTATATE and FDG PET.<h4>Conclusion</h4>This case demonstrates that medical stabilization achieves rapid biochemical control, providing time for serial anatomic imaging to localize occult ectopic ACTH sources. The gene discussed is POMC; the disease is adrenal gland hyperfunction.