Comparison of gold standards with common histopathologic evaluations in diagnosis of oral neurofibromas in pathology department of Shiraz Dental School

Introduction: Diagnosis of neurofibroma usually is based on the specific morphology and arrangement of mesenchymal cells in routine Hematoxylin and Eosin (H&E) sections, and detection of mast cells supports the diagnosis. Sometimes definite diagnosis from other mesenchymal lesions may be difficult. The aim of the present study was to compare S100 expression and mast cells count (as Gold Standard) with routine histopathologic diagnosis. Methods: In this cross-sectional analytical study, all cases of neurofibroma and compatible/ consistent with neurofibroma, that had been diagnosed in department of oral & maxillofacial pathology, school of dentistry, Shiraz, from 1986 to 2013, were enrolled. Immunohistochemistry was performed using S100 antibody and slides were stained by Giemsa. S100 labeling index, intensity and distribution as well as mast cells count were evaluated using light microscope. Results: Mast cells were present in 97% of cases that 56.4 % showed 1-200 cells/10HPF. 82 % of cases were positive for S100 that 40.7% showed 2-30% labeling index and 70.4% had moderate intensity for S100 staining. Conclusions: The comparison of routine histopathologic examination with gold standard method in Oral Pathology Department of Shiraz Dental School confirmed the routine histopathologic diagnosis in all cases, therefore no more evaluation may be required if a pathologist considers all routine diagnostic criteria.