title: Cerebral primitive neuroectodermal tumor in an adult male. A case report.
abstract: BACKGROUND
  Primitive neuroectodermal tumors (PNETs) are very rare. Malignant tumors of the cerebrum in young individuals are composed predominantly of undifferentiated cells, with moderate differentiation along either neuronal or glial lines. To our knowledge, cerebral PNETs in adults are extraordinarily rare and have been reported in only 11 cases, with little cytologic documentation in the literature. The cytopathologic, immunohistochemical and ultrastructural features of cerebral PNET arising in an adult male are presented.
  
  
  METHODS
  A cystic tumor, on computed tomography and magnetic resonance imaging, arose from the left frontal lobe in a 39-year-old man and contained histopathologic features of PNET. Specimens obtained from surgery revealed the presence of an undifferentiated type of PNET with moderate neuronal and glial differentiation and mild characteristic findings of peripheral PNET. The cytologic and histologic specimens showed evidence of a scattered pattern of blastic and undifferentiated tumor cells and a neural arrangement with Homer-Wright-like rosettes. Immunohistochemically, the tumor cells were glial fibrillary acidic protein, neuron-specific enolase, synaptophysin and CD-99 positive and epithelial membrane antigen, S-100 protein and vimentin negative. Ultrastructurally, neither microtubular structures nor intermediate filaments, except neurosecretory granules, were found in the tumor cells.
  
  
  CONCLUSIONS
  Both immunohistochemical and ultrastructural studies on cytologic and histologic slides were important for the diagnosis of PNET because of establishing not only undifferentiated tumor cells but also neural and glial differentiation.
authors: Departments of Pathology and Neurosurgery, National Cardiovascular Center, Osaka, Japan.
authors: K
authors: K
authors: Masuda
authors: C
authors: C
authors: Yutani
authors: K
authors: K
authors: Akutagawa
authors: S
authors: S
authors: Yamamoto
authors: H
authors: H
authors: Hatsuyama
authors: H
authors: H
authors: Ishibashi-Ueda
authors: M
authors: M
authors: Imakita
authors: H
authors: H
authors: Manaka
authors: J
authors: J
authors: Takahashi
authors: I
authors: I
authors: Nagata
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D005625:Frontal Lobe; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D018242:Neuroectodermal Tumors, Primitive / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure