Imaging features of calcifying pseudoneoplasms of the neuraxis

Objective To identify the imaging characteristics of calcifying pseudoneoplasms of the neuraxis (CAPNON) and do literature review.Methods Five patients of pathologically-proved CAPNON underwent preoperative MR examination,among which 4 underwent CT scan,2 underwent DSA examination and 1 underwent SPECT. All imaging data were retrospectively analyzed with the emphasis on imaging characteristics.Results Five patients of CAPNON with the diameter of 1.5 to 5.0 cm were found in five patients ( Male 4 ; Female 1 ; age 25 to 60 years old ).Three lesions were located in the skull base,one was located in the cervical spine and one in the foramen magnum and upper cervical segment. All patients underwent MRI examination and 4 of them also took CT scanning.On plain CT,all lesions showed obvious calcification.On T1WI all masses showed hypointensity,and on T2WI 4 of the lesions showed iso- or hypointensity and 1 heterogeneous signal intensity. On contrast-enhanced MR images, peripheral enhancement was demonstrated in 3 lesions,homogeneous enhancement was found in case and one lesion showed no enhancement. The pathologic analysis indicated that inside the lesions were abundant calcification,fibroepithelial tissue and mucoid matrix and no edema was detected around the lesions.Conclusions CAPNON displayed the predilection to male adults and the neuraxis was the predilection site.Calcification on CT images,hypointensity on MR images and peripheral enhancement will be helpful for the diagnosis of CAPNON,but the final confirmation still needs the pathologic results. Key words: Granuloma;  Magnetic resonauce imaging;  Tomography, X-ray computed