Mast cells in the human dura: Effects of age and dural bleeding

Background: Animal studies have shown that the dura mater contains mast cells. We investigated the density of mast cells in the human dura mater, and the changes associated with subdural haemorrhage (SDH). Methods: Samples of the human dura were stained with tryptase antibody and were examined for mast cells. We used control cases with no dural bleeding (n=9) and cases of fresh (n=24) and old (n=18) dural haemorrhage. Results: Mast cells were easily found in dural samples. The mean density in controls (11.05 cells per mm²) was less than that in fresh SDH (15.69), which was less than that in old SDH (23.09). Conclusions: Subdural haemorrhage is associated with an increase in dural mast cell density, and the density increases as the haematoma ages. We hypothesise that dural mast cells may contribute to neurogenic inflammation and the clinical features of subdural haemorrhage.