The value of touch imprint cytology in EUS-guided Trucut biopsy

BackgroundEUS-guided Trucut biopsy (TCB) enables the acquisition of tissue cores for histologic assessment. Touch imprint cytology (TIC) can be performed at the time of a biopsy to assess the adequacy of the sample; however, limited information is available on the diagnostic value of TIC of these specimens.ObjectiveTo investigate the diagnostic accuracy of TIC compared with a TCB.Patients and DesignConsecutive EUS-guided TCB and TIC (n = 109) were retrospectively and independently reviewed by a surgical pathologist (for the TCB) and a cytopathologist (for TIC) blinded to the final diagnoses.SettingUniversity of Iowa Hospitals and Clinics, Iowa.Main Outcome MeasurementsDiagnostic accuracy of a TCB, TIC, and combined TCB + TIC.ResultsThe diagnostic accuracy of a TCB was 92.7% (95% CI, 83.1%-97.3%), TIC was 82.6% (95% CI, 74.3%-88.6%), and TCB + TIC was 95.4% (95% CI, of 89.4%-98.3%). The diagnostic accuracy of a TCB alone was superior to TIC alone (P = .038); a TCB was diagnostic in 14 cases that were nondiagnostic by TIC. The addition of TIC allowed for the identification of 3 malignancies (2.8%) that were not identified on TCB alone. In 22 cases, TIC was considered diagnostic, but a TCB provided additional specific diagnostic information.LimitationsRetrospective study and relatively low numbers.ConclusionsTIC is a valuable tool for use in a EUS-guided TCB; TIC is independently diagnostically accurate, which allows for confidence in a rapid preliminary diagnosis, and it provides additional diagnostic value when combined with TCB.