Spontaneous venous aneurysms of the upper extremities and neck are rare and typically asymptomatic. We present the first reported case of a symptomatic, primary upper extremity venous aneurysm in a patient who initially presented with pulmonary emboli. A 22-year-old patient was admitted with chest pain, dyspnea, and a right axillary mass. Computed tomography revealed diffuse, bilateral pulmonary emboli in addition to a thrombosed axillary vein. Venography confirmed the diagnosis, and also revealed a subclavian vein stenosis at the crossing of the first rib. Pharmacomechanical thrombolysis, catheter-directed thrombolysis, and venoplasty were performed with adequate flow restoration, also revealing the presence of a previously thrombosed proximal brachial/distal axillary venous aneurysm. Hematologic testing showed a positive and persistent lupus anticoagulant. The patient declined surgical reconstruction and opted for long-term anticoagulation. At 24 months, the patient continued to remain symptom-free.