Abnormal [18F]fluorodeoxyglucose accumulation to tori tubarius in IgG4-related disease

Tubarial glands (TGs) are recently refocused gland tissues localized near the tori tubarius in the nasopharynx and their clinical relevance is not clear yet. IgG4-related disease (IgG4-RD) is a progressive fibrosing condition and salivary glands are well-affected lesions. The aim of the present study is to examine [18F]fluorodeoxyglucose ([18F]FDG) accumulation to the tori tubarius in IgG4-related disease (IgG4-RD). 48 patients with IgG4-RD who underwent positron emission tomography (PET) scanning with [18F]FDG were included and semi-quantitative analysis of [18F]FDG accumulation to tori tubarius was performed along with the clinical features and histopathological analysis. Of the 48 patients, abnormal [18F]FDG accumulation (metabolic tumour volume ≥ 1) to tori tubarius was observed in 15 (31.3%), all of whom had lesions in other head and neck glands. IgG4-RD patients with abnormal [18F]FDG accumulation to tori tubarius showed swollen nasopharyngeal walls around tori tubarius and forceps biopsy of the lesion revealed acinar cells and IgG4-positive plasma cells histologically. Abnormal [18F]FDG accumulation (maximum standard uptake value, metabolic tumour volume and total lesion glycolysis) to tori tubarius correlated with higher IgG4 and lower IgA serum concentrations. Abnormal [18F]FDG accumulation to tori tubarius can be observed in patients with IgG4-RD and the abnormal [18F]FDG accumulation to tori tubarius can be a clue of TG involvement in IgG4-RD.