IgG4-related systemic disease: an uncommon presentation for an uncommon disease.

IgG4-related systemic disease is an emerging disease process that manifests with a constellation of features, most commonly but not exclusive to swelling and tuberous growth in the lacrimal and salivary glands, potentially involving many other organ systems. This condition often prompts investigations into malignancy or needless radical surgical procedures. A 58-year-old male was presented to a rheumatologist after several biopsies were done that were suspicious for neoplasia, involving the lacrimal gland and lung. The diagnosis was confirmed when tissue from the lacrimal gland biopsy was reviewed with special stains for IgG4, performed at the Mayo Clinic. This patient is interesting because his disease included bilateral lacrimal glands--at different intervals, the submandibular glands, the lung, and the thyroid gland. His disease responded to immunosuppression. Literature has shown resolution of the tumors upon starting glucocorticoids or rituximab. Our patient was given a course of prednisone and methotrexate with normal follow-up CT chest and physical exam.