Intraoperative cytology when cryostat is not available. A 7-year experience in a Peruvian cancer center.

Background: Intraoperative cytology (IC) is an alternative to frozen-section (FS) diagnosis. We present our experience with and the diagnostic value of IC during a 7-year period when FS was not available in a Peruvian Cancer Center.

Material And Methods: This 7-year retrospective single-arm review study includes IC procedures performed by three pathologists between 2012 and 2018. These IC reports were reviewed independently by one pathologist and were correlated with the histologic diagnoses, which were used as the gold standard. All IC preparations (imprint, scrape, and crush smears) were stained with hematoxylin and eosin. IC interpretations were categorized as: malignant, benign, atypical, and "deferred to permanent sections." Sensitivity, specificity, and positive and negative predictive values were calculated by use of standard methods.

Results: A total of 1814 IC cases prepared from various organs obtained from 887 patients were reviewed. Malignant, benign, atypical, and "deferred to permanent sections" IC diagnoses were 26.3%, 68.9%, 3.7%, and 1.9%, respectively. Atypical and deferred cases were excluded from the statistical analysis; thus 1712 cases were found to be eligible. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall diagnostic accuracy were 91.6%, 97.7%, 94.1%, 96.7%, and 96%, respectively.

Conclusion: In experienced hands, IC is a rapid, cost-effective, and accurate alternative diagnostic modality for intraoperative diagnosis when FS is not available.