Immunoglobulin G4-Related Disease Affecting the Tonsil: Case Report and Literature Review

Immunoglobulin G4-related disease (IgG4-RD) can involve multiple sites throughout the body. The most commonly affected sites in the head and neck are the salivary and lacrimal glands, respectively. Very few cases of IgG4-RD manifesting in the tonsils have been reported. Herein, we report the imaging findings of a 49-year-old female with pathologically confirmed IgG4-RD after a right-side tonsillectomy. The lesion showed diffuse homogeneous enhancement and appeared isointense and slightly hyperintense on T1- and T2-weighted magnetic resonance imaging, respectively. Diffusion restriction was also observed, which was considered to be due to the large number of IgG4-rich plasmacytes, and could vary depending on the degree of fibrosis. As distinguishing IgG4-RD from other diseases based solely on imaging is challenging, it is important to consider differential diagnosis, and clinical considerations are essential.