INTRODUCTION AND AIMS: Primary burning mouth syndrome (pBMS) is a chronic orofacial pain disorder characterized by persistent oral burning sensations with clinically normal oral mucosa, frequently accompanied by comorbid psychological distress and impaired quality of life. The underlying neurobiological mechanisms of pBMS remain poorly elucidated, and existing structural neuroimaging studies have yielded inconsistent brain morphological findings. This study aimed to conduct a quantitative structural neuroimaging meta-analysis via seed-based d mapping to identify consistent grey matter alterations in patients with pBMS. METHODS: A quantitative meta-analysis of eligible voxel-based morphometry studies was conducted using seed-based d mapping (SDM-PSI) methodology to synthesize structural brain imaging data from 59 pBMS patients and 63 healthy controls and to further characterize consistent structural neuroimaging alterations associated with pBMS. Exploratory functional connectivity analyses were performed in two of the four included cohorts, using the same participant groups and without recruiting any additional independent subjects. RESULTS: The meta-analysis identified significantly reduced grey matter volume in the left medial superior frontal gyrus, a subregion of the medial prefrontal cortex, in patients with pBMS compared with healthy controls. CONCLUSION AND CLINICAL RELEVANCE: This structural neuroimaging meta-analysis identifies reduced grey matter volume in the left medial superior frontal gyrus as a potential neuroimaging signature of pBMS. These findings provide novel insights into the central neurobiological mechanisms of pBMS. Large-scale, longitudinal structural neuroimaging studies are required to further validate the present results.