Venous infarction of brainstem and cerebellum.

The authors describe 2 cases of posterior fosa venous infarction. A 56-year-old woman with essential thrombocytemia presented with fluctuating complaints of headache, nausea, vomiting, left-sided numbness-weakness, and dizziness and became progressively stuporous. Cranial magnetic resonance imaging (MRI) showed bilateral parasagittal fronto-parietal and left cerebellar contrast-enhancing hemorrhagic lesions. On magnetic resonance venography, the left transverse and sigmoid sinuses were occluded. The second patient, a 39-year-old woman, presented with acute onset of diplopia, numbness of the tongue, vertigo, and right-sided weakness following a gestational age stillbirth. MRI revealed lesions in the right half of midbrain and pons and in the superior part of the right cerebellar hemisphere. Digital subtraction angiography showed right transverse and sigmoid sinus occlusion. The authors suggest that one should investigate the possibility of venous infarction in the presence of posterior fossa lesions that are often hemorrhagic and are not within any arterial territory distribution but respect a known venous drainage pattern. Recognition of the observed clinical and neuroimaging features can lead to earlier diagnosis and, potentially, more effective management.