A 5-year-old child presenting with tumor-like primary angiitis of the central nervous system

Introduction: Primary angiitis of the central nervous system (PACNS) is a vasculitis confined to the CNS. A small proportion of the lesions may present as a tumor-like mass, which is rarely seen in children.Case presentation: A 5-year-old girl was admitted to our hospital because of an intermittent headache. Brain imaging suggested a space-occupying lesion in the right cerebral hemisphere. The final diagnosis was PACNS with a lymphocytic pattern by stereotactic brain biopsy. Her condition improved after immunotherapy.Conclusion: Pediatricians should consider the possibility of PACNS when encountering intracranial tumor-like lesions. Early diagnosis of tumor-like PACNS and prompt immunotherapy could improve the long-term prognosis and avoid surgery.