CASE PRESENTATION: A 17 year old high school wrestler, presented with one day history of dull pain, swelling and bluish discoloration of the left arm occurring after a wrestling match the day before. Patient denied any recent history of trauma, surgery, cancer, drug or steroid use as well as personal or family history of thrombophilia. Ultrasound revealed a non-occlusive thrombus in the left subclavian vein and he was started on IV heparin. A venogram demonstrated left subclavian vein occlusion with acute thrombus throughout the innominate vein. He then underwent catheter-directed thrombolytic therapy with alteplase and daily venograms. Due to persistent clot burden, balloon angioplasty was undertaken four days later. He was subsequently discharged on 3 months of warfarin and enoxaparin bridge therapy, and was scheduled for TOS investigations as an outpatient. 2 months after this episode, a diagnosis of DBCL was made during investigations for persistent cough.