title: Leukemia/lymphoma in cerebrospinal fluid: distinguishing between cases that performed well and poorly in the College of American Pathologists Interlaboratory Comparison Program in Non-gynecologic Cytology.
abstract: BACKGROUND
  Although the cytologic features of leukemia/lymphoma in cerebrospinal fluid specimens are well known, the correlation of these features with the ability of cytologists to identify this tumor have not been well studied.
  
  
  OBJECTIVE
  To identify the morphologic features of leukemia/lymphoma in cerebrospinal fluid that are associated with good performance and poor performance in an educational interlaboratory comparison program; and to identify the morphologic features associated with how well a slide performs with regard to its reference diagnosis.
  
  
  METHODS
  The performance of 147 cases of leukemia/lymphoma in the College of American Pathologists Interlaboratory Comparison Program in Non-gynecologic Cytology was analyzed. The cytologic features of a subset of 31 cases composed of relatively equal numbers of Romanowsky-stained and Papanicolaou-stained specimens were further evaluated, and those that performed poorly (n = 12) were compared with those that performed extremely well (n = 19).
  
  
  RESULTS
  For all cases of leukemia/lymphoma in the program, the rate of misclassification as benign for cases with Papanicolaou stain was significantly higher than for those with Romanowsky stain (9.5% vs 2.6%, P < .001). Compared with cases that performed well, slides that performed poorly were more likely to have less than 200 abnormal cells (42% vs 5%, P = .02). The size of the tumor cells and preservation were not significant.
  
  
  CONCLUSIONS
  Cases of specimens of leukemia/lymphoma in cerebrospinal fluid are more likely to be misdiagnosed as benign if they are Papanicolaou-stained or have 200 abnormal cells.
authors.affiliation: Department of Pathology, Baptist Hospital of Miami, Miami, Fla, USA.
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Renshaw
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Hughes
authors.forename: Edward
authors.initials: E
authors.lastname: Wang
authors.forename: Jennifer
authors.initials: J
authors.lastname: Haja
authors.forename: David
authors.initials: D
authors.lastname: Wilbur
authors.forename: Michael R
authors.initials: MR
authors.lastname: Henry
authors.forename: Ann T
authors.initials: AT
authors.lastname: Moriarty
mesh_terms: D003581:Cytodiagnosis / Q000379:methods / Q000592:standards*; D003951:Diagnostic Errors / Q000706:statistics & numerical data*; D006801:Humans; D007755:Laboratories, Hospital / Q000592:standards; D007938:Leukemia / Q000134:cerebrospinal fluid* / Q000175:diagnosis; D008223:Lymphoma / Q000134:cerebrospinal fluid* / Q000175:diagnosis; D010338:Pathology, Clinical / Q000592:standards*; D011237:Predictive Value of Tests; D011785:Quality Assurance, Health Care; D012955:Societies, Medical