Brain biopsy in children with primary small-vessel central nervous system vasculitis.

OBJECTIVE: Primary angiitis of the central nervous system in childhood (cPACNS) is an immune-mediated inflammatory process directed toward blood vessels in the central nervous system. It has been associated with variable clinical and radiological presentations, and devastating consequences without treatment. Brain biopsy is required for definitive diagnosis. The objective of this study was to characterize the clinical and histopathological features of brain biopsies in small-vessel cPACNS (SVcPACNS).
METHODS: A single-center prospective cohort study of children diagnosed with cPACNS from 1998 to 2008 was performed. All patients with negative cerebral angiography and brain biopsy were included. Patient data were reviewed for clinical, laboratory, and radiological characteristics at presentation. Standardized brain biopsy review protocols were established, with independent analysis by 2 neuropathologists. Histopathology was correlated with collected clinical data.
RESULTS: A total of 13 SVcPACNS patients were included. Ages ranged from 5 to 17 years. Presenting features included seizures (85%), headache (62%), and cognitive decline (54%). Brain biopsy confirmed SVcPACNS in 11 patients with intramural lymphocytic infiltrate. Two had nonspecific perivascular inflammation only. All 6 nonlesional biopsies yielded a diagnosis of SVcPACNS. Lack of specific histological features correlated with prolonged time to biopsy, prior steroid treatment, and inadequate specimen sampling.
INTERPRETATION: In children presenting with new onset severe headaches, seizures, or cognitive decline, SVcPACNS and brain biopsy should be considered. Lesional biopsies are preferred; however, nonlesional biopsies may succeed in yielding the diagnosis. Steroid treatment prior to biopsy and inadequate biopsy sampling may obscure the diagnosis in true cases of SVcPACNS.