Abstract Disclosure: A.B. Figueiredo: None. C.A. Baptista: None. C.R. Xavier: None. A.K. Nascimento: None. R.L. Dolci: None. A.L. dos Santos: None. J. Ethel: None. C.T. da Silva: None. N.M. Scalissi: None. J.V. Lima: None. Introduction: Patients with Cushing's syndrome (CS) have a 4-fold increased risk of thrombosis, due to increased synthesis of Von Willebrand factor and cortisol-stimulated fibrinogen, as well as increased synthesis of type 1 plasminogen activator inhibitor. The first 4 weeks after surgery are the period most susceptible to thromboembolism due to the worsening of the coagulation profile associated with the sudden reduction in the level of cortisol and its anti-inflammatory activity, leading to a thrombotic and inflammatory state. Case report: A 28-year-old woman, evaluated for bariatric surgery, was admitted to the emergency department complaining of dyspnea and palpitations that had started the day before. Supplementary oxygen therapy was instituted, the electrocardiogram showed a S1Q3T3 pattern, and chest angiotomography identified a thrombus in the arch of the right pulmonary artery and another in the left pulmonary artery. Thrombolysis was performed in the emergency room, followed by anticoagulation with intravenous heparin, resulting in clinical stability. He had typical symptoms of hypercortisolism such as obesity, early-onset hypertension, hirsutism, amenorrhea, and proximal weakness. During preparation for bariatric surgery, CS was suspected, with suppression test with dexamethasone and nocturnal salivary cortisol confirming hypercortisolism, and peripheral test with DDAVP and pituitary magnetic resonance imaging (MRI) confirming Cushing's disease by 8x4 mm adenoma. It was opted for clinical treatment with ketoconazole and anticoagulation for 6 months with transsphenoidal surgery. In the immediate postoperative period, it was planned to keep the patient off anticoagulants for the shortest possible time, with enoxaparin being restarted after surgery. On the 5th postoperative day, laboratory tests revealed cortisol of 1.7 mcg/dL and ACTH of 6.3 pg/mL, suggesting remission of the disease and supplementation with prednisone. On the 8th postoperative day, the patient complained of sudden dyspnea and desaturation, which led to the investigation of a new episode of pulmonary embolism. which was confirmed by chest angiotomography. Thus, a new Pulmonary Embolism was confirmed, this time with the use of full dose enoxaparin. The patient was referred to the ICU, where he received oxygen support and heparin infusion, with gradual clinical improvement and later, with anticoagulation for Warfarin with an INR goal of 2.5-3.0 and after 22 days of surgery, the patient achieved clinical stability and was discharged from the hospital. Conclusion: This case highlights the association of CS and thromboembolic events, especially Pulmonary Embolism. Presentation: Saturday, June 17, 2023