抄録
A 69-year-old woman presented with headache and short memory disturbance. Computed tomography (CT) demonstrated a small cystic mass lesion in the left temporal lobe. CT and magnetic resonance imaging showed that this lesion enlarged with repeated hemorrhages, associated with progressive amnesia and headache during 3 years follow up. Surgery demonstrated a well-demarcated hard mass lesion in the medial temporal lobe through a transcortical approach after opening left sylvian fissure. The lesion was located entirely in the brain parenchyma and was removed en-bloc after cutting some capillary-like vessels on the capsule. The histological diagnosis was encapsulated old hematoma. The histological findings suggested that expansion of the lesion was due to multiple bleedings from the sinusoidal vessels in the capsule fed by small feeding arteries. The mass effect due to the expansion of the encapsulated hematoma caused progressive short-term amnesia and headache, which were completely resolved by the surgical removal.
