Pituitary ACTH-secreting tumour presents with variety of clinical features: normal cortisol secretion and ACTH-immunopositive staining and mild hypercortisolism without typical features of Cushings disease. We present a 53-year-old male with history of hypertension. First visit (2005): visual loss, bitemporal hemianopsia in campimetry and in MRI pituitary adenoma (2.5 cm) invading cavernous sinus and suprasellar cister. Hormonal study supported panhypopituitarism. After transsphenoidal surgery, there was a tumour rest (9 mm) with left cavernous sinus invasion. Pathology: atypical pituitary adenoma and ACTH-immunopositive staining. There were normal campimetry and persistence of hormonal deficit. In 2006, he received photon radiotherapy (50 Gy) with radiologic stability. After 6 years, left eyelid ptosis (cranial nerves IIIVI palsy) appeared. In replacement therapy with hydrocortisone, levothyroxine, and testosterone, presented TSH <0.05 μgUI/ml, FT4 1.1 ng/dl, prolactin 3.2 ng/ml, testosterone 3.7 ng/ml, cortisol 10 μg/dl, ACTH 53 pg/ml, and IGF1 24 ng/ml. MRI: pituitary solid lesion (1.7 cm) with left cavernous sinus. Transsphenoidal surgery was performed. Ophthalmoplegia persisted. Pathology: pituitary adenoma ACTH-producer, Ki <1%, P53 75%. After surgery: TSH <0.005 μgUI/ml, FT4 1.2 ng/dl, cortisol 10 μg/dl, and ACTH 64 pg/ml. Hydrocortisone was suspended and an ACTH-test was performed: peak cortisol 14.4 μg/dl. Corticosteroid therapy was maintained. 6 months after surgery: MRI with tumour rest (11 mm) in the left cavernous sinus and right cavernous sinus (16 mm). PETTCFDGmetionine: metabolically active injury in both cavernous sinuses. Hormone study: cortisol 17 μg/dl and ACTH 97 pg/ml, so we suspended hydrocortisone. Without treatment cortisol was 16 μg/dl. Nugent test: cortisol 18 μg/dl. FSR (50 Gy) was administered. After 2 months: cortisol 16 μg/dl, ACTH 127 pg/ml, and UFC 320 μg/24 h. We began cabergoline 1 mg/week. The development of Cushings syndrome in patients with silent corticotropinomas determines a factor of aggressiveness in these tumours. Intensification with cabergoline was performed, and temozolomide was planned in case of progression.