title: Intraoperative diagnosis of nervous system lesions.
abstract: OBJECTIVE
  To determine the accuracy of comparative cytologic and frozen section intraoperative diagnosis in neuropathology and the relevance of diagnostic accuracy during both craniotomic and stereotactic biopsies and to provide further data on rare and/or diagnostically controversial lesions.
  
  
  METHODS
  Both cytologic and frozen section preparations were employed in the intraoperative diagnosis of 85 consecutive central and peripheral nervous system lesions obtained from classical surgery (70 samples, 4 of which were intramedullary) and stereotactic biopsies (15 samples).
  
  
  RESULTS
  Combining cytologic and frozen section details allowed a fair diagnosis in 81 cases (95.29%), confirmed on paraffin sections. In the remaining cases intraoperative misdiagnosis was due to technical-staining defects (1 case); absence of tumor differentiation, resolved only by ultrastructural examination (2 cases); and marked tumor heterogeneity, resolved by wide tissue sampling and immunohistochemistry (1 case).
  
  
  CONCLUSIONS
  Besides providing a general description of cytologic and frozen section criteria useful in intraoperative diagnostic neuropathology and adding further details about some problematic and/or rare entities, our work confirmed: (1) the usefulness of comparative cytologic and frozen section examination in the intraoperative diagnosis of central nervous system lesions, (2) the relevance of the accuracy of intraoperative diagnosis during both craniotomy and stereotaxis, including intramedullary samples; and (3) the importance of fair "conduct" in intraoperative neuropathology, always comparatively considering morphologic and clinicoradiologic data.
authors.affiliation: Department of Experimental Medicine and Pathology, La Sapienza University, Rome, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Di Stefano
authors.forename: L F
authors.initials: LF
authors.lastname: Scucchi
authors.forename: L
authors.initials: L
authors.lastname: Cosentino
authors.forename: C
authors.initials: C
authors.lastname: Bosman
authors.forename: A
authors.initials: A
authors.lastname: Vecchione
mesh_terms: D002490:Central Nervous System / Q000473:pathology*; D002493:Central Nervous System Diseases / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D007430:Intraoperative Care; D017933:Peripheral Nervous System / Q000473:pathology*; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis* / Q000473:pathology