Castleman's Disease with Pulmonary Artery Aneurysm: A Rare Presentation of Behçet's Disease.

Diagnosing Behcet's disease (BD) in a patient already diagnosed with Castelman's disease (CD) is rare. There are only a few cases reported in the literature and all of them were diagnosed as BD prior to the patient experiencing symptoms and signs of CD. We present a patient who was initially diagnosed as having CD. However, after being managed with chemotherapy, specifically after the fourth cycle, the patient was found to have an incidental finding of pulmonary artery aneurysm, which led to the diagnosis of BD. For that, he received the appropriate management of high-dose steroid, azathioprine, and oral anticoagulant. Currently, the patient is doing well, and the latest computed tomography scan showed complete resolution of his pulmonary aneurysm. We suggest taking a thorough history from all patients with BD symptoms and signs, especially in CD patients as they may overlap, for early diagnosis and to prevent complications.