Right proximal sub-clavian artery pseudoaneurysm masquerading as right upperzone opacity of lung

Right proximal subclavian artery pseudoaneurysms are uncommon conditions with a relatively small number of recorded instances to date. Such cases might be challenging to diagnose since the patient may have symptoms that are similar to those of other illnesses, including lung cancer. The diagnosis is aided by imaging methods including contrast-enhanced computed tomography (CECT) chest and computed tomography angiography, as well as a high level of clinical suspicion. We present a rare case of a 23-year-old man with no history of lung disease or trauma, who had a complaints of change in voice, difficulty in swallowing and haemoptysis. Right-sided upper zone homogeneous opacity was seen on the chest X-ray. CECT revealed large, well-defined solid cystic areas that extended up to the posterosuperior aspect of the right upper thoracic region. Aneurysm rupture with active contrast leak. Pulmonary angiography revealed the presence of a pseudoaneurysm in the middle mediastinum on the right side, originating from the right proximal subclavian artery. The patient was operated on, and the right subclavian artery and innominate artery pseudoaneurysm were repaired. If subclavian artery pseudoaneurysms are large, they can cause compression symptoms. For compressive symptoms, open surgical resection and vascular reconstruction are required. In a patient with hemoptysis and opacities on chest imaging, arterial aneurysm should be considered as a differential diagnosis alongside lung mass. Before considering a biopsy from the lesion, further evaluation with CECT should be performed