Solution: For a complete discussion of this disease, I would point you t an excellent article in RadioGraphics (September 2011 RadioGraphics, 31, 1379-1402). Basics are that what has been historically called "Autoimmune Pancreatitis" is actually a manifestation of a more systemic disease process called IgG4-related Sclerosing Disease. There can be, and often is involvement of numerous extrapancreatic organs such as the bile ducts, gallbladder kidneys, RP, thyroid, lung, lacrimal glands and orbits, mediateinum, lymph nodes, prostate, salivary glands, etc. The involvement can be metachronous or synchronous and is associated with elevated levels of IgG4, numerous IgG4 positive plasma cells that infiltrate various organs, and this leads to organ fibrosis. In this case, there is involvement of the orbital muscles, kidneys, and hilar lymph nodes. This disease does respond well to corticosteroid therapy, so it is a very important diagnosis to make. Unlike most autoimmune diseases, it has a male predominence and disease recurrence is common, so follow up is important.