title: Intracranial solitary fibrous tumor/ hemangiopericytoma with osteoclast-like multinucleated giant cells: comparison with giant cell-rich solitary fibrous tumor.
abstract: OBJECTIVE
  Intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a mesenchymal neoplasm that typically presents in adults as a dural-based lesion. The presence of giant cells in these tumors is a rare occurrence.
  
  
  METHODS
  We studied a case of intracranial SFT/HPC with unusual multinucleated, osteoclast-like giant cells and compared it to the so-called giant cell angiofibroma (i.e., giant cell-rich solitary fibrous tumor) withattention to STAT6 immunohistochemistry.
  
  
  RESULTS
  A 73-year-old man developed a right frontoparietal dural mass that was completely resected. Histology demonstrated a hypercellular neoplasm consisting of spindle to oval cells and scattered osteoclast-like multinucleated giant cells (MGCs), with distinctive "staghorn" blood vessels. Necrosis and brisk mitotic activity were present. The spindle cell component showed strong focal CD34 and nuclear STAT6 immunohistochemical labeling, while CD68 and CD163 were positive in MGCs. No nuclear STAT6 reactivity was detected in MGCs. By contrast, nuclear STAT6 staining was present in three cases of giant cell angiofibroma (i.e., giant-cell rich solitary fibrous tumor), both in the spindle cell component and MGCs.
  
  
  CONCLUSIONS
  Intracranial SFT/HPC is characterized by nuclear STAT6 immunoreactivity as its soft tissue counterparts. The presence of osteoclast-like MGCs is an unusual finding in this neoplasm, which is distinct from giant cell-rich solitary fibrous tumor.
authors.forename: M Adelita
authors.initials: MA
authors.lastname: Vizcaíno
authors.forename: Justin
authors.initials: J
authors.lastname: Bishop
authors.forename: Rajni
authors.initials: R
authors.lastname: Sharma
authors.forename: Karim
authors.initials: K
authors.lastname: Refaey
authors.forename: Alfredo
authors.initials: A
authors.lastname: Quiñones-Hinojosa
authors.forename: Fausto J
authors.initials: FJ
authors.lastname: Rodriguez
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D015726:Giant Cells / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008577:Meningeal Neoplasms / Q000473:pathology*; D008579:Meningioma / Q000473:pathology*; D010010:Osteoclasts / Q000473:pathology; D050800:STAT6 Transcription Factor / Q000032:analysis / Q000096:biosynthesis; D054364:Solitary Fibrous Tumors / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D050800:STAT6 Transcription Factor; C494101:STAT6 protein, human