title: Cytology of chordoid meningioma: a series of five cases with emphasis on differential diagnoses.
abstract: BACKGROUND
  Chordoid meningioma is a rare meningioma variant characterised by epithelioid cord-like tumour cells in a myxoid stroma. It is classified as grade II (World Health Organization) tumours, as they have a tendency to behave more aggressively than traditional meningiomas and have a greater likelihood of recurrence.
  
  
  OBJECTIVE
  To report the features of intraoperative imprint smears of five cases of chordoid meningioma.
  
  
  METHODS
  The intraoperative squash smears were reviewed for cellularity, cellular atypia, mitotic figure, cytoplasmic vacuolation, intranuclear inclusion, presence of a cohesive cord of tumour cells, whorl-like structure, psammoma bodies, chronic inflammatory cells (lymphocytes and plasma cells), background mucin and necrosis.
  
  
  RESULTS
  All cases were of moderate to high cellularity, with cohesive cords of bland tumour cells possessing uniformly round nuclei with smooth nuclear outline, stippled chromatin and small nucleoli, with cytoplasmic vacuolation and chronic inflammatory cells in the background. Intranuclear inclusions (80%) and whorl-like structures (60%) were also common. Necrotic background, psammoma bodies or mitotic figures were consistently absent.
  
  
  CONCLUSIONS
  The cytological features of chordoid mengiomas are distinctive, and intraoperative imprint diagnosis is feasible.
authors.affiliation: Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong. philiplui@cuhk.edu.hk
authors.forename: Philip C W
authors.initials: PC
authors.lastname: Lui
authors.forename: Tony K F
authors.initials: TK
authors.lastname: Chau
authors.forename: Steve S
authors.initials: SS
authors.lastname: Wong
authors.forename: Patrick P L
authors.initials: PP
authors.lastname: Lau
authors.forename: Gary M K
authors.initials: GM
authors.lastname: Tse
authors.forename: Teresa M M
authors.initials: TM
authors.lastname: Thomas
authors.forename: Ho Keung
authors.initials: HK
authors.lastname: Ng
mesh_terms: D000328:Adult; D000368:Aged; D002467:Cell Nucleus / Q000473:pathology; D016545:Choroid Plexus Neoplasms / Q000473:pathology* / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D045586:Intranuclear Inclusion Bodies / Q000473:pathology; D007430:Intraoperative Care / Q000379:methods; D008279:Magnetic Resonance Imaging; D008297:Male; D008577:Meningeal Neoplasms / Q000473:pathology* / Q000601:surgery; D008875:Middle Aged; D014617:Vacuoles / Q000473:pathology