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.