Perianeurysmal vasogenic oedema (PAVO) following aneurysm embolisation: a unique case of asymptomatic long-term progression and review of the literature.

Perianeurysmal vasogenic oedema is a recognised although rare phenomenon following endovascular treatment of certain intracranial aneurysms. We present a unique case of asymptomatic perianeurysmal vasogenic oedema following bare platinum coil embolisation of an incidentally discovered right middle cerebral artery aneurysm that slowly increased over a period of 6 years before stabilising and regressing. During this time, the coiled aneurysm per se remained completely stable on serial magnetic resonance angiography.

A rare suspected case of chronic nodular granulomatous herpes simplex encephalitis in an adult.

Herpes simplex encephalitis is the most common sporadic viral encephalitis in the western world, HSV-1 (herpes simplex virus) being the mostly commonly implicated serotype. The disease is usually monophasic, although patients may relapse weeks, months or years after initial infection. This chronic granulomatous inflammatory process is almost exclusively described in children and rarely forms discrete enhancing parenchymal nodules. We present the clinical and radiological features of an unusual case of chronic nodular granulomatous herpes encephalitis with enhancing "mass-like" nodules in an adult. To the author's knowledge, this is the first reported case of macroscopic "mass-like" nodular granuloma formation in an adult.

De novo cavernoma developing from an asymptomatic thalamic microhemorrhage.

Cavernomas are low-flow vascular lesions affecting approximately 0.5% of the population. Historically these have been considered congenital lesions, but numerous reports have demonstrated de novo formation. The phenomenon is well documented in patients with the familial disease form and after cranial radiotherapy, but outside of these circumstances there is scant evidence as to the potential etiology. The authors present a 5 year MRI series of a 56-year-old woman with no known risk factors demonstrating cavernoma formation and growth from previously normal brain. The patient was consistently asymptomatic during follow-up. Given the history and imaging findings, we propose that cavernomas can arise directly from angiogenic proliferation secondary to microhemorrhage from unrelated causes.

Arterial origin subdural hematoma and associated pial pseudoaneurysm following minor head trauma.

The vast majority of primary acute subdural hematomas following trauma are venous in origin. We report a very rare case of a primary acute subdural hematoma following minor head trauma that was arterial in origin and was associated with a pial cortical branch pseudoaneurysm. The patient was managed conservatively, and follow-up imaging demonstrated complete resolution of both lesions.