A Secret Revealed: The Coexistence of a Pheochromocytoma and Independent Adrenocorticotropic Hormone-Secreting Cushing Syndrome Within the Same Adrenal Gland.

Adrenal incidentalomas are increasingly encountered in clinical practice. When functional, they are typically associated with the secretion of a single hormone. However, dual hormonal activity is exceptionally rare, particularly in cases where pheochromocytomas are associated with adrenocorticotropic hormone (ACTH) production, as seen in ectopic Cushing syndrome. We report a unique case of a single adrenal mass, discovered incidentally during a thoracic CT scan performed as part of post-COVID follow-up. Biochemical investigations revealed elevated 24-hour urinary metanephrines, a non-suppressible cortisol level after an overnight dexamethasone suppression test, and normal ACTH levels, suggesting an atypical secretory profile. Histopathological examination confirmed the mass as a pheochromocytoma. Notably, clusters of ACTH-expressing cells were found surrounding the tumor. These cells did not form a distinct mass and were interpreted as part of the same lesion. It has been hypothesized that they may correspond to Leydig-like cells resulting from an embryological migration defect. Additionally, a paracrine interaction between chromaffin cells and ACTH-expressing cells, potentially mediated by co-peptides, may contribute to this unique hormonal behavior. This case adds to the exceptionally rare reports of dual hormonal activity in adrenal tumors and offers new insights into the pathophysiological mechanisms underlying this unusual endocrine presentation.