Management of squamous intraepithelial lesion as a new cytological diagnostic class in the Bethesda system in oral cytology: Correlation between the Bethesda system and the Papanicolaou/three-grade classifications

Objective : This retrospective study was aimed at elucidating the management of Squamous Intraepithelial Lesion (SIL) classified according to the Bethesda System in oral cytology.Study Design : Cytology specimens collected from June 2007 to September 2014 at the Department of Oral and Maxillofacial Surgery, Shimane University Hospital (1867 cases ; male, 845 ; female, 1022), were examined. The cytological findings were classified according to the Bethesda System (NILM, LSIL, HSIL, SCC and IFN), as well as according to the conventional Papanicolaou (Pap.) and three-grade classifications. “Atypical cells suspected” was defined as Class Ⅲ, which was further subdivided into Subclass Ⅱ-Ⅲ (LSIL), Ⅲ, and Ⅲ-Ⅳ (HSIL).Results : The cytological diagnoses according to the Bethesda System were NILM (1298 cases), LSIL (158 cases), HSIL (267 cases), SCC (132 cases) and inadequate specimen (12 cases). The three-grade classification was as follows : negative (1298 cases), suspected (425 cases), and positive (132 cases). Histopathological examination was performed for LSIL (58 cases) and HSIL (128 cases). SCC was detected in 17 cases with LSIL (29.3%) with LSIL, and 68 cases with HSIL (53.1%).Conclusion : Histopathological examination is recommended for SIL. It is necessary to investigate the detailed diagnostic criteria to distinguish between LSIL and HSIL, as well as between NILM and SIL.