Introduction and importance: Thoracic outlet syndrome (TOS) is a rare syndrome caused by compression of one of the three neurovascular structures in their passage from the cervical area toward the axilla and proximal arm either at the interscalene triangle, the costoclavicular triangle, or the sub coracoid space. The mainstay of management is nonsurgical; however, surgery may be needed when patients persist with symptoms despite conservative management and when vascular structures are involved. Symptoms are non-specific and require high clinical awareness since this pathology tends to affect otherwise healthy young patients. Case presentation: We present the case of a 45-year-old female without any past medical history. She was active and did plenty of exercises. After a high-intensity routine without any guidance, she presented with acute upper limb swelling with pain. After further examination, a venous thoracic outlet syndrome was identified and treated without complications. Clinical discussion & conclusion: Venous TOS is a rare pathology associated with high long-term morbidity and disability if left untreated; heightened clinical awareness of the possibility of acute thrombosis obstructing venous return and producing these rare symptoms should lead the medical team to assess the patient further and lead to the appropriate medical and surgical intervention.