Spinal calcifying pseudoneoplasm of the neuraxis (CAPNON) and CAPNON-like lesions: CAPNON overlapping with calcified synovial cysts

Calcifying pseudoneoplasm of the neuraxis (CAPNON) is a rare tumour-like fibro-osseous lesion in the neuraxis including the spine. It is diagnosed by the presence of the following histological features: granular amorphous to chondromyxoid fibrillary cores with calcification/ossification, peripheral palisading of spindle to epithelioid cells, variable fibrous stroma, and foreign body reaction with multinucleated giant cells, as well as positive …