Subgemmal neurogenous plaque: clinical and microscopic evaluation of 7 cases

Subgemmal neurogenous plaques (SNPs) are biphasic neural structures found on the posterolateral border of the tongue. Fewer than 40 cases have been reported and only a few were symptomatic. The present report details the features of 7 cases of SNP retrieved from the files of a single institution. Clinical and histopathological data were reviewed and immunohistochemical analysis was performed for S100, CD56, neuron-specific enolase, epithelial membrane antigen, CK7, CK8, CK14, and CK20. All cases showed similar morphological and immunohistochemical characteristics. Neural markers highlighted the biphasic pattern and CK7, CK8, and CK20 were detected on taste buds confined to the epithelium adjacent to the SNPs. Five patients presented pain/discomfort as the main symptom. Symptomatic SNPs seems to be more common than previously reported, presenting as focal burning on the posterolateral border of the tongue.