Increased leukotriene C4 and vasogenic edema surrounding brain tumors in humans.

Leukotrienes are pharmacologically active compounds that promote vascular permeability. In this study we sought to determine whether tissue leukotriene-like immunoreactivity was increased in intracranial tumors associated with peritumoral edema. In 20 patients undergoing craniotomy tissue specimens were immediately frozen after removal and tissue leukotriene C4 levels were determined by radioimmunoassay. An index of peritumoral edema was estimated from preoperative contrast-enhanced computed tomographic scans. There was a significant correlation between brain edema and tissue leukotriene levels (p less than 0.003). Metastatic tumors (n = 8) had the highest leukotriene C4 level at 13.8 +/- 8.5 pg/mg tissue (mean +/- SE) and the highest index of edema 5.7 +/- 1.8. The mean leukotriene C4 level in the gliomas (n = 5) was 6.2 +/- 2.3 pg/mg tissue and the edema index was 2.1 +/- 0.6. There was no edema and no neoplasm in the temporal lobes removed for seizure (n = 2), and their level of leukotriene C4 was 0.4 +/- 0.1 pg/mg tissue. The formation of leukotriene C4 is stimulated by intracranial tumors. Leukotrienes increase blood-brain barrier permeability and may be important in the formation of vasogenic edema surrounding tumors.