Pseudo-obstruction on single-phase CTPA: unilateral pulmonary vein atresia as the cause of 50 years of hemoptysis.

backgroundHemoptysis in adults is rarely caused by congenital vascular anomalies, leading to frequent diagnostic oversight. Unilateral pulmonary vein atresia is a rare congenital anomaly in adults that may mimic chronic thromboembolic pulmonary disease (CTEPD) on single-phase computed tomography pulmonary angiography (CTPA). This radiologic mimicry frequently leads to misdiagnosis and inappropriate anticoagulation. We report a case illustrating this diagnostic pitfall and the critical role of dual-phase imaging. CASE PRESENTATION: A 58-year-old woman presented with worsening hemoptysis. Despite a 50-year history of intermittent bleeding, she had recently been diagnosed with CTEPD based on flow artifacts mimicking filling defects seen on single-phase CTPA and started on oral anticoagulants, which exacerbated her symptoms. The discordance between the extensive radiological occlusion and her stable cardiopulmonary status prompted re-evaluation. Dual-phase CTPA demonstrated delayed arterial opacification and absent pulmonary veins, confirming congenital unilateral pulmonary vein atresia. The initial "thrombus" was identified as a flow artifact caused by hemodynamic stasis. Anticoagulation was immediately ceased. The patient underwent successful superselective embolization of hypertrophied systemic collaterals. She remained asymptomatic at follow-up.

conclusionsCongenital unilateral pulmonary vein atresia can simulate pulmonary embolism on pulmonary arterial-phase imaging, creating a pseudo-obstruction. Clinicians should suspect this anomaly in adults with long-standing hemoptysis when imaging findings of extensive thrombosis do not align with clinical presentation. Dual-phase CTPA is the critical problem-solving tool to differentiate true pulmonary artery thromboembolism from flow artifacts, thereby preventing dangerous anticoagulation and guiding appropriate management.