Subgemmal neurogenous plaque: a series of six cases and a literature overview

The study aims to describe six subgemmal neurogenous plaque (SNP) cases and compile the previously available data on SNP. Searches on PubMed, Web of Science, Embase, Scopus, and a two-step study selection were performed to compile data from case reports/series of SNP published in English literature. Our six patients (range 29–63 years) had SNP in the posterior lateral border of the tongue. Four of them were associated with lymphoepithelial cysts. A total of 15 studies, comprising 116 patients, were included in this overview. There was a slight predilection for female patients (56.0%) in the 5th (22.4%) and the 7th (23.9%) decades. The lateral border of the tongue (66.4%) was the most common anatomical location. The major manifestation was nodule/papule. Histologically, the presence of taste buds ( n = 40/ 34.5%), superficial neural plexus ( n = 32/ 27.6%), deep nerve fascicles ( n = 32/ 27.6%), ganglion cells ( n = 41/ 35.3%), and lymphoid tissue ( n = 22/ 19.0%) was mainly reported. Surgical removal was the primary approach, with a low recurrence rate. Although largely unknown, SNP is a regular and likely frequent structure located in the tongue. The findings emphasize the importance of describing clinicopathological patterns of SNP as a differential diagnosis of neural lesions that affect the tongue.