Highlighting the importance of early diagnosis in progressive multi-organ involvement of IgG4-related disease: A case report and review of literature.

IgG4-related disease (IgG4-RD) is an increasingly recognized pathological entity that tends to involve multiple organs with an elevated level of serum IgG4, which is easily misdiagnosed owing to sharing common clinical features with a variety of other diseases. Here, we report an interesting IgG4-RD case of a woman with progressive multi-organ involvement for over 19 years, started with swollen eyelids, dry eye and mouth, and polydipsia and hydruria. Imaging diagnosis revealed diffuse enlargement of the parotid glands, enlargement of the head of the pancreas, pulmonary infection and interstitial lung. Serological tests showed a remarkable elevation of the serum IgG4, and cytological analysis further revealed a large amount of lymphoplasmacytic infiltration into the focal lobule, and IgG4-positive cell infiltration in bladder mucosa. Therapeutically, the patient responded well to steroid therapy, and thus, she was diagnosed as IgG4-RD suspicious. This report highlights the importance of an early diagnosis in this autoimmune disease and suggests that patients with a clinically unclear cause of inflammation, swelling and refractory glands, rhinitis, pancreatitis, hypophysitis, and/or interstitial pneumonia should be considered for IgG4-RD. The plasma IgG4 level and lymphoplasmacytic infiltration may be useful indexes for screening, and a low dose of steroid maintaining therapy may offer benefits for patients with IgG4-RD.