An 18-year-old Caucasian man presented with a sudden onset right hemiparesis. On examination, he had objective evidence of an upper motor neuron lesion affecting the right side of his body. CT scan showed a left thalamic haemorrhage. MRI, gradient echo and cerebral angiogram showed no structural lesion and the cause of the bleeding was ultimately attributed to the use of cocaine. During the subsequent 2 years the patient had two further similar episodes, with an MRI eventually demonstrating a cerebral cavernous malformation. This was excised using frameless stereotactic surgery, following which the patient made an uneventful recovery.