Accidente cerebrovascular bulbar lateral con trayecto extracraneal de la arteria cerebelosa póstero-inferior / Lateral medullary stroke with extracranial course of the postero- inferior cerebellar artery

Presentamos dos casos de accidente cerebrovascular en sujetos con trayecto extracraneal de la arteria cerebeloso póstero-inferior. Caso 1: varón de 21 años, quien presentó ataxia y dismetría derecha luego de un traumatismo cervical en un partido de rugby. Caso 2: mujer de 56 años, quien inició con vértigo y hemiparesia izquierda luego de esfuerzo físico intenso. En ambos casos, los estudios angiográficos mostraron un trayecto extracraneal de la arteria cerebelosa póstero-inferior. Este vaso raramente se origina por debajo del foramen magno, en relación cercana con las primeras tres vértebras cervicales y la articulación atlanto-axial. En este nivel, está expuesta a daño mecánico causante de disección, como por ejemplo trauma directo, manipulación cervical abrupta o extensión cefálica prolongada. Por lo tanto, en pacientes con accidente cerebrovascular de región lateral de bulbo y trayecto extracraneal de la arteria cerebelosa póstero-inferior se debería considerar esta asociación.

We present two cases of lateral medullary stroke in subjects with extracranial trajectory of the postero-inferior cerebellar artery. Case 1: a 21-year-old male who presented ataxia and right dysmetria after cervical trauma in a rugby match. Case 2: 56-year-old woman, who started with vertigo and left hemiparesis after intense physical effort. In both cases, the angiographic studies showed an extracranial trajectory of the posterior inferior cerebellar artery. This vessel rarely originates below the foramen magnum, in close relationship with the first three cervical vertebrae and the atlanto-axial joint. At this level, it is exposed to mechanical damage causing dissection, such as direct trauma, abrupt cervical manipulation or prolonged cephalic extension. Therefore, this association should be considered in patients with stroke of the lateral region of the bulb and extracranial trajectory of the posterior-inferior cerebellar artery.

Distal calcarine fusiform aneurysm: a case report and review of literature.

A 50 year old female who was operated for atrial septal defect 8 years back, presented with clinical features suggestive of subarachnoid haemorrhage (grade I, Hunt and Hess). CT scan of brain revealed haemorrhage in all the supratentorial basal cisterns, sylvian cistern and small haematoma in the left occipital lobe. Conventional CT and MR angiography revealed aneurysm in relation to distal part of the calcarine branch of the left posterior cerebral artery (PCA). Left occipital craniotomy in prone position followed by deep dissection in the occipital lobe showed fusiform aneurysm of the distal part of the calcarine branch. PCA aneurysms constitute only 0.2 to 1% of all intracranial aneurysms and among them distal PCA aneurysms are most rare, constituting only 1.3%. They too are mostly seen at the bifurcation of the PCA. The present case however, is unique in the sense that it has developed as a fusiform aneurysm in the distal part of the calcarine branch. To the best of our knowledge this is rare among the rarest.