Traumatic aneurysm of the cortical middle cerebral artery.

To cite: Varma S, Banh L, Smith P. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2017219301 DESCRIPTION A right-handed man aged 79 years presented with increasing confusion following a mechanical fall with head strike 2 weeks prior. CT demonstrated a left frontoparietal convexity subacute subdural haematoma (SDH) measuring 3 mm in depth and with 5 mm of midline shift to the right (figure 1). There was no skull fracture. Initial examination revealed no localising neurological deficit and he was admitted for observation. On day 3, the patient developed intermittent episodes of rightsided weakness and expressive dysphasia. Contrast MRI showed expansion of the SDH to 10 mm in thickness, and also demonstrated a 9 mm vividly enhancing focus within the haematoma overlying the frontal lobe (figure 2). The lesion enhanced on the arterial and venous phases of contrast CT (figure 3). Digital subtraction angiography demonstrated the lesion to be a 6 mm sidewall aneurysm of the cortical middle cerebral artery (MCA) (figure 4). Craniotomy was performed, the aneurysm trapped and excised with preservation of distal blood flow, and the SDH evacuated (figure 5). Histology demonstrated a lack of a tunica media or adventitia, consistent with pseudoaneurysm. The patient had mild residual weakness but otherwise recovered well and was transferred for rehabilitation. Traumatic intracranial aneurysms (TICA) account for only 1% of intracranial aneurysms, but are important because of their propensity to cause delayed bleeding. Several mechanisms can result in TICA, including closed blunt head trauma, missile injury, penetrating injury and iatrogenic injury. The average time from traumatic injury to haemorrhage from a TICA is ∼21 days, and in those with ruptured aneurysms, mortality has been reported to approach 50%. Traumatic middle cerebral artery aneurysms (TMCAA) are a subtype of TICA and in 93% of cases occur in the cortical segment of the MCA,