title: Rare association of secondary superficial siderosis caused by a fourth ventricle hemorrhagic ependymoma mimicking a cavernoma: Case report and literature review.
abstract: BACKGROUND
  The association of a hemorrhagic tumor with secondary superficial siderosis (SS) is a relatively rare although well described phenomenon.
  
  
  METHODS
  We present the case report of a 35-year-old male with a history of drowsiness, hypoacusia, drop attacks, and multidirectional nystagmus during the last 2 months, who presented with acute obstructive hydrocephalus caused by a fourth ventricle mass displaying radiological signs of repeated intra and extratumoral hemorrhage with SS. He underwent gross surgical removal of the solid component of the tumor. Microscopic examination revealed an ependymoma with atypical features, including prominent angiomatous formations and internal chronic hemorrhages with hemosiderin deposits, resembling a cavernoma. The scarce tumoral component, which extended around these cavernous vessels, lacked the gross typical features of fibrillary stroma or perivascular pseudorosettes.
  
  
  CONCLUSIONS
  To our knowledge, including the present case, there are 45 published reports of tumors associating secondary SS. Besides ependymoma, no other hemorrhagic lesion, tumoral or vascular, has been previously published associating a fourth ventricle location with secondary SS. The present case represents the fifth with this finding, and we strongly suggest ependymoma as a presumptive diagnosis when this rare association is encountered. In addition, this appears to be the first case reported in the scientific literature of a hemorrhagic fourth ventricle ependymoma mimicking both, radiologically and histologically, a cavernous malformation.
authors.affiliation: Department of Neurosurgery, Hospital Universitario Ramón y Cajal, Madrid, Spain.
authors.forename: Eduardo E
authors.initials: EE
authors.lastname: Espinosa Rodríguez
authors.affiliation: Department of Neurosurgery, Hospital Universitario Ramón y Cajal, Madrid, Spain.
authors.forename: Rodrigo Carrasco
authors.initials: RC
authors.lastname: Moro
authors.affiliation: Department of Radiology, Hospital Universitario Ramón y Cajal, Madrid, Spain.
authors.forename: Juan S
authors.initials: JS
authors.lastname: Martínez San Millán
authors.affiliation: Department of Pathology, Hospital Universitario Ramón y Cajal, Madrid, Spain.
authors.forename: Héctor G
authors.initials: HG
authors.lastname: Pian Arias
keywords: Cerebral ventricle neoplasms; fourth ventricle; subarachnoid hemorrhage