Calcifying pseudoneoplasms of the neuraxis: CT, MR imaging, and histologic features.
OBJECTIVE
Non-neoplastic, calcified, fibro-osseous lesions known as "calcifying pseudoneoplasms of the neuraxis" (CAPNON) are rare and can occur anywhere within the neuraxis. The radiologic and histopathologic characteristics of this unusual entity are not well understood. We present the largest series reviewing the MR imaging features of CAPNON.


METHODS
The MR and CT imaging features in 4 patients with a pathologic diagnosis of "calcifying pseudoneoplasms of the neuraxis" were retrospectively reviewed. A neuropathologist also analyzed the histopathologic features for typical and atypical patterns.


RESULTS
Imaging features were strikingly similar for all 4 patients. All lesions appeared T1 and T2 hypointense without vasogenic edema. All tumors had dense calcification, and 3 tumors showed minimal linear internal or rim enhancement on MR imaging.


CONCLUSIONS
CAPNON may mimic more common vascular malformations or neoplasms and are often not considered in the differential diagnosis of calcified lesions. CAPNON should be included in the differential diagnosis of a calcified mass with marked T1 and T2 hypointensity and limited to no enhancement. Careful CT and MR imaging evaluation can suggest this entity, and this preoperative recognition may help subsequent management decisions.
Department of Radiology, University of California, San Francisco, Calif., USA. Ashley.aiken@radiology.ucsf.edu
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Aiken
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Akgun
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Tihan
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Barbaro
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Glastonbury
D002114:Calcinosis / Q000150:complications* / Q000175:diagnosis*; D002493:Central Nervous System Diseases / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D014057:Tomography, X-Ray Computed / Q000379:methods*