We present a patient with Cushing disease apparently suppressing sarcoidosis, which was unmasked following surgical resection of a pituitary adrenocorticotropin (ACTH)-producing microadenoma. Case report and a short review of the literature published in this area. A 46-year-old Caucasian woman presented with symptoms of hypercortisolism such as progressive weight gain, Cushingoid appearance, proximal myopathy, easy bruising, and amenorrhea. Blood testing including inferior petrosal sinus sampling uncovered an ACTH-producing microadenoma in the right aspect of the anterior pituitary gland for which the patient underwent transphenoidal resection. Maintenance corticosteroid therapy was implemented, and the signs and symptoms of Cushing disease began to resolve. Three months after surgery, multiple erythematous painful nodules developed on the patient's arms. Erythema nodosum (EN) was diagnosed clinically and a suspicion of underlying sarcoidosis was substantiated by lung imaging and elevated plasma interleukin (IL)-2 receptor. One month later, the lesions spontaneously resolved without therapy other than maintenance glucocorticoid replacement. Physicians should be aware that patients undergoing successful treatment of Cushing syndrome may have a flare-up or emergence of a corticosteroid-responsive disease.