IgG4-related systemic disease in a Native American man.

IgG4-related systemic disease is a recently described entity that can elude even the most astute diagnostician. Patients with the disease, characterized by the infiltration of polyclonal IgG4-positive plasmacytes, can present with single or multi-organ involvement. Manifestations include dacryoadenitis, sialadenitis, thyroiditis, pneumonitis, retroperitoneal fibrosis, pancreatitis, sclerosing cholangitis, tubulointerstitial nephritis, prostatitis, and hypophysitis. We describe a biopsy-confirmed case with extensive multi-organ involvement, including hypophysitis, dacryoadenitis, retroperitoneal fibrosis and tubulointerstitial nephritis. By reporting this case, we hope to bring IgG4-related systemic disease to the attention of the broader medical community as it is an elusive disease that commonly responds to systemic corticosteroids.