Behçet's Disease Presenting With Massive Haemoptysis Due to Pulmonary Artery Aneurysms: A Case Report.

An information technology worker of South Asian heritage in his 30s presented with haematemesis and central chest pain. Initial evaluation, including oesophagogastroduodenoscopy, was unremarkable. Subsequent imaging revealed multiple pulmonary artery aneurysms. Blood tests showed a negative autoimmune profile and raised inflammatory markers. Infectious, thromboembolic and connective-tissue differentials were excluded. A history of oral ulcers with genital ulceration, together with vascular involvement, fulfilled International Criteria for Behçet's Disease (ICBD). Given the life-threatening risk, we initiated intravenous methylprednisolone followed by cyclophosphamide, later transitioning to azathioprine with a structured steroid taper. Haemoptysis ceased promptly, and follow-up imaging showed aneurysm resolution. This case illustrates how haemoptysis can masquerade as gastrointestinal bleeding and emphasises the need to consider pulmonary artery aneurysms in young patients with compatible systemic features, where early imaging and rapid immunosuppression may be lifesaving.