[A clinical analysis of 5 patients with infratentorial primary angiitis of central nervous system].

To explore the clinical characteristics of infratentorial primary angiitis in central nervous system(PACNS). A total of 5 cases diagnosed as infratentorial PACNS in the neurology department of Navy General Hospital of PLA in 2015 were enrolled in the study. The clinical, imaging and pathological data were collected and analyzed. All the 5 cases were male with the median onset age of thirty-four. Five cases presented with dizziness, two with headache, three with walking unstable, two with facial numbness and one with dysarthria. Rising pressure of cerebrospinal fluid (CSF) (190-245 cmH(2)O, 1 cmH(2)O=0.098 kPa) was found in 4 cases by the lumbar puncture, mildly increased number of leukocyte in 2 cases [(12-28)×10(6)/L], increased CSF protein in 3 cases(540-979 mg/L) and increased IgG index in 3 cases(0.84-1.45). Pons lesions were revealed by magnetic resonance imaging(MRI)in 4 cases, brachium pontis lesions in 2 cases, cerebellum lesions in 2 cases, one with midbrain lesion in 1 case, unilateral lesions in 4 cases and bilateral lesion in 1 case. Different degree of edema and mass effect were shown in all lesions by MRI. Patch like enhancement was found by contrast MRI in 5 cases and meningeal enhancement in 2 cases. Elevation of choline(Cho)peak was found by magnetic resonance spectroscopy(MRS)in 4 cases, reduction of N-acetyl aspartate(NAA) peak in 3 cases, appearance of lactate peak in 1 case and lipid peak in another case. Arterial spin labeling(ASL) was performed in 4 cases and no hyperperfusion was found. Susceptibility weighted imaging(SWI) was performed in 3 cases and microhemorrhage in the lesions was found in 2 cases and normal in 1 case. Magnetic resonance arteriography(MRA) was performed in 1 case and no stenosis was found. Digital subtraction arteriography(DSA) was performed in 1 case and multiple stenosis of the intracranial arteries was showed. Two cases had taken the stereotactic brain biopsy and the histopathologic diagnosis was angiitis. Five cases were treated with methylprednisolone and cyclophosphamide was added on in 1 case. Good prognosis was found in all cases. Infratentorial PACNS mostly attacks middle-aged males. The lesions tend to locate in unilateral pons, brachium pontis, cerebellum and midbrain. Hemorrhage or microhemorrhage in lesions is often found by SWI and no hyperperfusion is shown by ASL, which would be useful to distinguish PACNS from malignant tumors. Given the limitations of brain biopsy in clinical practice, clinical and imaging features would be helpful to diagnose PACNS.