MRCP2-2363
A 67-year-old man presents with sudden-onset left upper limb and lower limb weakness. He has a history of headaches but is otherwise healthy, never smoked, and drinks two pints of beer a day. On examination, he has a left-sided motor and sensory deficit, an ejection systolic murmur at the right second intercostal space, and a mass in the left upper quadrant of his abdomen that moves downwards on inspiration. His blood pressure is 157/89 mmHg, heart rate 70 bpm and regular, temperature 36.9 °C, and oxygen saturation 97%. Laboratory investigations reveal elevated haemoglobin, white cell count, platelets, and leukocyte alkaline phosphatase score, as well as high levels of sodium, potassium, urea, and creatinine. What is the most likely diagnosis?