Autoimmune pancreatitis: an update.

Autoimmune pancreatitis (AIP) is the pancreatic manifestation of a systemic fibroinflammatory disorder. It has been recognized as a distinct clinical entity, only recently. Multiple organs, such bile ducts, salivary glands, kidneys and lymph nodes, can be involved either synchronously or metachronously. It is one of the few autoimmune conditions that predominantly affects male subjects in the fifth and sixth decades of life. Obstructive jaundice is the most common presenting symptom but the presentation can be quite nonspecific. There are established diagnostic criteria to diagnose AIP, most of which rely on a combination of clinical presentation, imaging of the pancreas and other organs (by CT scan, MRI and endoscopic retrograde pancreatography), serology, pancreatic histology and response to steroids to make the diagnosis. It is imperative to differentiate AIP from pancreatic cancer owing to the vastly different prognostic and therapeutic implications. AIP responds dramatically to steroid treatment but relapses are common. Relapse of AIP can often be retreated with steroids. As the collective experience with this condition increases, a better understanding of the natural history of this disease is emerging.