Diagnostic utility of touch imprint cytology for intraoperative assessment of surgical margins and sentinel lymph nodes in oral squamous cell carcinoma patients using four different cytological stains

Background OSCC is most commonly associated with positive surgical margins. The important cause of loco regional recurrence is histologically positive or closed margins. Clear surgical margins might favor the patient with a better prognosis and prevent repetitive surgeries. The present study was designed to the diagnostic utility of touch imprint (TI) smears using H and E, Pap, Giemsa and Feulgen stains, so that they can be used on a routine basis. Materials and methods A total of 720 smears from 130 margins resected from 32 patients who underwent surgical resection of OSCC were prospectively evaluated. The slides were fixed in alcohol and randomly divided into four different batches for staining with H&E, rapid Pap, Giemsa, Feulgen stain. TI of 30 sentinel lymph node were fixed in 95% alcohol, stained by (H&E) and evaluated by two independent observers. The results were compared with gold standard histopathology. Results H&E stain showed sensitivity 44%, rapid Pap 35%, Giemsa 29% and Feulgen stain 25%. Positive predictive value—100% for all the four stains. NPV–H&E 70%, Pap 66%, Giemsa 62%, Feulgen 59%. Diagnostic test accuracy of H&E stained smears was higher 72%, compared to Pap 67%. Giemsa 65%, and Feulgen 63%. In lymph nodes, Specificity was 94.74%, PPV 90.91%, NPV 94.74%, diagnostic accuracy 93.33%. Conclusion TIC is effective in identifying an inadequate or severe dysplasia margin comparable to gold standard histopathology. It might be used to intraoperatively identify metastases in sentinel lymph nodes in clinically N0 Patients.