Granuloma formation and occlusion of an unruptured aneurysm after wrapping

Excessive granulomatous foreign-body reaction is a very rare complication after wrapping of intracranial aneurysms. The pathogenetic mechanisms underlying this process are unknown. We report on a patient who developed a space-occupying granulomatous abscess after wrapping of an unruptured aneurysm of the M2/M3 bifurcation. The patient underwent revision craniotomy for abscess removal. The aneurysm was explored and found to be completely thrombosed and excluded from the circulation. Exuberant granulomatous foreign-body reaction was pathologically confirmed and Candida parapsilosis was isolated from the pus. The patient underwent an antifungal treatment regimen and recovered with no residual neurological deficits. Our findings support the assumption that a low-grade infectious process might trigger excessive inflammatory reaction after wrapping. We suggest that this process may also result in complete thrombosis of cerebral aneurysms, which is otherwise a rarely observed phenomenon.