KIT and submandibular gland disorder: Interestingly, although the number of c-kit-positive mast cells was not significantly increased in IgG4-related submandibular gland disease as compared to that in sialolithiasis and normal submandibular glands, the number of strongly cytoplasmic IgE-positive mast cells was significantly increased in IgG4-related submandibular gland disease.