Diagnostic value of cytology in oral ulcer and comparison with histopathology and direct immunofluorescence

Rapid diagnosis of pemphigus vulgaris (PV) is an important task in patient's prognosis and treatment. Although PV is routinely diagnosed through investigation of pathology specimens and direct immunofluorescence assays, Tzanck smear can be used as rapid, inexpensive, and easily used test to confirm its clinical diagnosis. This study aimed to determine the diagnostic value of Tzanck smear in erosive oral lesions of PV and also determine its sensitivity and specificity for diagnostic purposes. A total of 68 patients with erosive/ulcerated oral lesions were included in this study and divided into PV (case group) vs other causes of erosive oral lesions (control group). From all participants, two Tzanck smears were prepared for both Giemsa and hematoxylin-eosin (H&E) staining. For definite diagnosis, histopathology and direct immunofluorescence evaluations were performed based on clinical findings. The sensitivity of acantholytic cells in Tzanck smear of erosive oral lesions of PV cases was 80.5% (for both Giemsa and H&E staining), whereas specificity values of Giemsa and H&E staining were 84.6% and 96.3%, respectively. Based on our findings, the Tzanck smear of erosive oral lesions is a simple, quick, and inexpensive test for screening and primary diagnosis of PV.