Chronic Sclerosing Sialadenitis of the Submandibular Gland as the Initial Symptom of IgG4-Related Disease: A Case Report

摘要

Immunoglobulin G4-related disease (IgG4-RD) is a systemic condition accompanied by tumefactive lesions, dense lynnphoplasmacytic infiltrate rich in IgG4-positive plasma cells, storiform fibrosis in various organs, and, frequently, elevated serum IgG4 levels. Chronic sclerosing sialadenitis (also termed Kuttner's tumor) is thought to be a lesion of IgG4-RD; thus, IgG4-related sialadenitis may be the initial symptom of IgG4-RD. We herein report a 64-year-old Japanese female with IgG4-related chronic sclerosing sialadenitis of the right submandibular gland and retroperitoneal fibrosis, who subsequently developed tubulointerstitial nephritis and pancreatitis. She was referred to our Department for treatment of swelling of the right submandibular gland; preoperative imaging studies suggested a malignant tumor. We extirpated the submandibular glands bilaterally and diagnosed IgG4-related chronic sclerosing sialadenitis pathologically. Subsequently, the patient's serum IgG4 concentration increased, and lesions in the retroperitoneum, kidney, and pancreas were confirmed by imaging. Although the radiological characteristics of these lesions mimicked malignancy, steroid treatment was commenced based on the pathology of the submandibular gland and elevated serum IgG4 level. This caused the lesions to disappear, indicating that the patient had experienced IgG4-related retroperitoneal fibrosis, tubulointerstitial nephritis, and pancreatitis. No relapse was detected for 4 years 8 months after surgery. A pathological diagnosis is crucial to exclude the possibility of malignancy and to make treatment decisions when lesions are evident in other organs. In addition, periodic evaluation of the serum IgG4 concentration and imaging of the whole body are warranted in long-term follow-up.