title: Ependymoma and intraparenchymal calcifying pseudoneoplasm of the neural axis: incidental collision or unique reactive phenomenon?
abstract: The so-called "calcifying pseudoneoplasm of the neural axis" is a rare tumefactive lesion presumed to be reactive in nature. To our knowledge, association with a true neoplasm has not been previously reported. We recently encountered the case of a 67-year-old woman who underwent resection of an incidentally discovered cerebellar cystic mass with a distinct, calcified component. Histology demonstrated a partially ossified, lobulated, chondrocalcific lesion surrounded by chronic inflammation, spindle to epithelioid cells, and occasional multinucleated giant cells-all features of calcifying pseudoneoplasm of the neural axis. A low-grade ependymoma associated with marked piloid gliosis was found contiguous to the lesion. The unique combination of an ependymoma with marked reactive gliosis and a calcifying pseudoneoplasm supports the reactive nature of the latter.
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First Street, SW, Rochester, MN 55905, USA. rodriguez.fausto@mayo.edu
authors.forename: Fausto J
authors.initials: FJ
authors.lastname: Rodriguez
authors.forename: Bernd W
authors.initials: BW
authors.lastname: Scheithauer
authors.forename: Daryl R
authors.initials: DR
authors.lastname: Fourney
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Robinson
mesh_terms: D000368:Aged; D001927:Brain Diseases / Q000150:complications* / Q000473:pathology; D002114:Calcinosis / Q000150:complications* / Q000473:pathology; D002528:Cerebellar Neoplasms / Q000150:complications* / Q000473:pathology; D004806:Ependymoma / Q000150:complications* / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D014057:Tomography, X-Ray Computed