Incidental finding of subgemmal neurogenous plaque upon retrospective evaluation of oral lymphoepithelial cysts

Purpose We aimed to compare the histomorphological features of oral lymphoepithelial cysts (OLC) in different locations of the oral cavity and to verify the association between oral lymphoepithelial cysts and subgemmal neurogenous plaque (SNP) on biopsies from the lateral border of the tongue. Methods All cases diagnosed as OLC from the Oral Pathology Service at the School of Dentistry/University of São Paulo were retrieved. For all the cysts located in the tongue, their association to SNP was analyzed. Immunohistochemical staining against S100 was performed to confirm the diagnosis of SNP. Results Thirty-one cases were selected for morphological analysis and SNP was identified in 40% of cases, all of them positive for S100. In these cases, macroscopic analysis demonstrated two independent fragments. Microscopic analysis showed that cysts located in the floor of the mouth and ventral surface of the tongue showed less intense exocytosis, less formation of lymphoid follicles, and predominantly a moderate inflammatory infiltrate. Conclusions OLC have a similar histological pattern regardless the location within the oral cavity and. In some cases, the biopsy specimen may be accompanied by a SNP as an adjacent independent structure.