title: Unusual skull tumors with psammomatoid bodies: a diagnostic challenge.
abstract: OBJECTIVE
  We describe a series of three diagnostically challenging, histologically similar fibro-osseous skull masses.
  
  
  METHODS
  The cases were identified in our archives among 50,000 neuropathology specimens. A comprehensive review of the histological, immunohistochemical, ultrastructural, and imaging features as well as the clinical outcome was performed.
  
  
  RESULTS
  The routine histology was similar in all 3 cases and showed spindle cell proliferations with frequent calcospheres or psammomatoid bodies. There was no evidence of an underlying subdural component. Immunohistochemistry for the meningioma markers EMA and SSTR2A raised the possibility of intraosseous meningioma, as all 3 lesions were convincingly positive for epithelial membrane antigen (EMA) and 1 lesion was convincingly positive for the somatostatin receptor subtype 2A (SSTR2A); weak, questionable positivity for SSTR2 was present in the remaining 2 cases. In addition, electron microscopy was available in 1 case and showed features consistent with meningioma.
  
  
  CONCLUSIONS
  Overall, the findings were most consistent with intraosseous meningioma. Primary intraosseous meningiomas are rare lesions that may present a diagnostic challenge. It is important to consider meningiomas in the differential diagnosis, as extradural meningiomas are associated with an increased risk of recurrence and may occasionally undergo malignant transformation. .
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Richardson
authors.forename: Maria-Magdalena
authors.initials: MM
authors.lastname: Georgescu
authors.forename: Payal
authors.initials: P
authors.lastname: Kapur
authors.forename: Helena
authors.initials: H
authors.lastname: Hwang
authors.forename: Samuel L
authors.initials: SL
authors.lastname: Barnett
authors.forename: Jack M
authors.initials: JM
authors.lastname: Raisanen
authors.forename: Chunyu
authors.initials: C
authors.lastname: Cai
authors.forename: Kimmo J
authors.initials: KJ
authors.lastname: Hatanpaa
mesh_terms: D000328:Adult; D049109:Cell Proliferation; D003937:Diagnosis, Differential; D018214:Fibroma, Ossifying / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology*; D006801:Humans; D008297:Male; D008579:Meningioma / Q000175:diagnosis / Q000235:genetics / Q000473:pathology; D008854:Microscopy, Electron; D008875:Middle Aged; D018396:Mucin-1 / Q000235:genetics; D017481:Receptors, Somatostatin / Q000235:genetics; D012886:Skull / Q000473:pathology*; D012888:Skull Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology*
chemical_list: D018396:Mucin-1; D017481:Receptors, Somatostatin; C574734:SSTR2 protein, human