Soft Tissue Neoplasms Causing Apparent Venous Thoracic Outlet Syndrome

Venous thoracic outlet syndrome (vTOS) usually results from compression of the subclavian vein classically as a result of narrowing of the costoclavicular space. We report 2 rare cases of soft tissue neoplasms resulting in apparent vTOS. The first case is a 46-year-old female with a 2-year history of intermittent unilateral shoulder pain, who was initially diagnosed with intervertebral disk herniation. Cervical fusion was performed; however, her symptoms progressed and she additionally developed paresthesias and venous congestion. Computed tomography (CT) angiogram demonstrated a 13-cm-encapsulated mass within the subscapularis muscle compressing the axillary vein. Radiological findings suggested lipoma. She subsequently underwent complete resection via a transaxillary approach with extension along the lateral border of the latissimus. Final pathology confirmed an intramuscular lipoma. The second case is a 21-year-old female who presented with acute onset of unilateral chest wall pain, palpable nodularity, and venous congestion. CT chest showed pulmonary embolism and an anterior chest wall mass. An initial attempt at resection was aborted due to proximity of the mass to the subclavian vein. The mass enlarged on serial imaging, measuring 3.8 cm in greatest dimension. Additionally, tumor thrombus was seen, and a subsequent ultrasound-guided biopsy was positive for high-grade synovial sarcoma. Positron emission tomography scan showed a pulmonary nodule that was resected thoracoscopically with pathology confirming metastatic synovial sarcoma. Subsequently, she underwent neoadjuvant chemoradiation followed by successful resection of the chest wall mass. An extended infraclavicular approach with a secondary transaxillary incision was utilized to achieve adequate exposure and margins. Final pathology was consistent with preoperative biopsy. Venous reconstruction was not needed. Although rare, an extrinsic mass as a cause of apparent TOS should be in the differential diagnosis. Surgical approach is based on tumor type, location, and proximity to the neurovascular bundle.