Inflammatory pseudotumors of the central nervous system: report of 3 cases and a literature review.

Inflammatory pseudotumors (IPs), mostly benign lesions characterized by fibrotic ground tissue and polyclonal mononuclear infiltrate, may affect all organ systems. IPs originating in the central nervous system (IP-CNS) are very rare, and their distinct histopathologic features are poorly characterized. Three otherwise healthy patients (age 8, 15, and 17 years) presented with focal neurologic symptoms (seizures, n = 2; headaches, n = 1), corresponding to a left temporal, left occipital, and left frontal IP, respectively, extending from meningeal structures into brain tissue. After resection, no recurrence was observed in patient 1 during 5 years of follow-up, whereas patient 2 developed a rapidly progressive local recurrence and a second intracerebral lesion despite antiviral, immunosuppressive, antibiotic, and radiation therapy. In patient 3, who also showed local recurrences, sequential histopathologic investigations revealed transformation to a semimalignant fibrohistiocytic tumor. In this patient, anaplastic lymphoma kinase (ALK) expression was also positive, whereas it was negative in patient 1. A detailed literature analysis confirmed that most IP-CNS arise from dural/meningeal structures (n = 34). Intraparenchymatous (n = 7), mixed intraparenchymatous/meningeal (n = 4), and intraventricular lesions (n = 7) or IP extending per continuitatem from intracerebral to extracerebral sites (n = 5) were rare. The recurrence rate was 40% within 2 years in general. It was increased after incomplete resection and in female patients (multivariate Cox regression model, P < 0.02). Although rare, IP-CNS are important differential diagnoses among tumor-like intracranial lesions. Their potential risk of malignant transformation and high risk of recurrence necessitate close follow-up, especially when resection is incomplete. Prospective multicenter trials are needed to optimize classification and treatment of this rare inflammatory lesion.

Neurological complications of acute and persistent Epstein-Barr virus infection in paediatric patients.

Neurological complications of Epstein-Barr virus (EBV) have been reported almost exclusively in the course of acute primary infections. The role of EBV in paediatric neurological disease was investigated prospectively over a 2-year period, searching for acute primary, chronic, and reactivated EBV infections. Active EBV infections were diagnosed in 10/48 patients, including two with acute primary EBV infections (cranial neuritis and cerebellitis), one with chronic active infection (T/NK cell lymphoma with cranial neuritis), and seven with reactivated infections. Among these seven patients, three showed "Alice in Wonderland" syndrome, one facial nerve palsy, one progressive macrocephaly, and two prolonged encephalitic illness. The prognosis was good except for the patient with lethal T/NK cell lymphoma and the two girls with encephalitic illness. Despite steroid treatment, these girls suffered prolonged cognitive impairment and epileptic seizures. Both developed left-sided hippocampal atrophy, and one of them hippocampal sclerosis. Like primary infections, reactivated EBV infections cause neurological complications in a considerable number of paediatric patients, lead to serious long-term complications, and may contribute to the pathogenesis of hippocampal lesions.