Arachnoid granulation affected by subarachnoid hemorrhage.

The purpose of this study was to investigate using light microscopy the fibrocellular components of arachnoid granulations affected by mild and severe subarachnoid hemorrhage. The erythrocytes were in the channels delimited by collagenous and elastic bundles and arachnoid cells, showing their tortuous and inter-communicating row from the pedicle to the fibrous capsule. The core portion of the pedicle and the center represented a principal route to the bulk outflow of cerebrospinal fluid and erythrocytes. In the severe hemorrhage, the fibrocellular components are disorganized, increasing the extracellular channels. We could see arachnoid granulations without erythrocytes, which cells showed big round nucleus suggesting their transformation into phagocytic cells.