title: Confocal microscopy and exfoliative cytology.
abstract: BACKGROUND
  Early detection of potentially malignant lesions and invasive squamous-cell carcinoma in the oral cavity could be greatly improved through techniques that permit visualization of subtle cellular changes indicative of the neoplastic transformation process. One such technique is confocal microscopy. Combining rapidity with reliability, an innovative idea has been put forward using confocal microscope in exfoliative cytology.
  
  
  OBJECTIVE
  The main objective of this study was to assess confocal microscopy for cytological diagnosis and the results were compared with that of the standard PAP stain.
  
  
  METHODS
  Confocal microscope, acridine orange (AO) stain, PAP (Papanicolaou) stain. The study was designed to assess confocal microscopy for cytological diagnosis. In the process, smears of patients with (clinically diagnosed and/or suspected) oral squamous cell carcinoma as well as those of controls (normal people) were stained with acridine orange and observed under confocal microscope. The results were compared with those of the standard PAP method.
  
  
  METHODS
  Samples of buccal mucosa smears from normal patients and squamous cell carcinoma patients were made, fixed in 100% alcohol, followed by AO staining. The corresponding set of smears was stained with PAP stain using rapid PAP stain kit. The results obtained were compared with those obtained with AO confocal microscopy.
  
  
  RESULTS
  The study had shown nuclear changes (malignant cells) in the smears of squamous cell carcinoma patients as increased intensity of fluorescence of the nucleus, when observed under confocal microscope. Acridine orange confocal microscopy showed good amount of sensitivity and specificity (93%) in identifying malignant cells in exfoliative cytological smears.
  
  
  CONCLUSIONS
  Confocal microscopy was found to have good sensitivity in the identification of cancer (malignant) cells in exfoliative cytology, at par with the PAP method. The rapidity of processing and screening a specimen resulted in saving of time. It added a certain amount of objectivity to the process of arriving at a diagnosis.
authors.affiliation: Department of Oral Pathology, Staff Quarters, Sarda Estate, Aditya Dental College and Hospital, Beed, Maharashtra, India.
authors.forename: Shyam Prasad
authors.initials: SP
authors.lastname: Reddy
authors.forename: Pratibha
authors.initials: P
authors.lastname: Ramani
authors.forename: Purshotam
authors.initials: P
authors.lastname: Nainani
keywords: Acridine orange staining; PAP (Papanicolaou) stain; confocal microscopy; exfoliative cytology; squamous cell carcinoma