Abstract A 56-year-old woman was admitted to the Emergency Department for profuse diarrhoea, associated with hypokaliemia and dehydration. A subclavian venous catheter was inserted after she had a cardiac arrest. Six days later, the subclavian and innominate veins were thrombosed. Prophylactic low molecular weight heparin was then replaced by sodium heparinate. The patient's platelet count decreased to 65 G · 1 −1. It was nevertheless decided to remove her villous tumour. After the operation, the patient became shocked, with worsening thrombocytopaenia (15 G · 1 −1). She was unresponsive to fluid replacement. Transoesophageal echocardiography (TEE) was carried out, as pulmonary arterial catheterization was considered too dangerous. A « whitethromboembolus was discovered in the right pulmonary artery. Embolectomy was successfully performed without extracorporeal circulation. Flow was completely restored in the main pulmonary artery, but only partially in the right branch. Oral anticoagulation was started postoperatively. It is concluded that TEE might be a very helpful technique to promptly diagnose acute pulmonary embolism ; moreover, it could be an alternative to pulmonary angiography, especially in patients in a poor state.