When DVT turns into surgical catastrophe: undiagnosed case of May-Thurner syndrome leading to retroperitoneal haematoma and fatal bleeding

May-Thurner syndrome (MTS) is an unusual cause of deep venous thrombosis; even rarer is the spontaneous rupture of collaterals around the thrombosed common iliac vein due to MTS. We present a case of MTS which presented with left leg swelling and abdominal mass due to retroperitoneal haemorrhage.