The diagnosis of AIP can be a clinical challenge, because the price of misdiagnosis is heavy. Although AIP can mimic any know pancreatic disease, in practice, the chief differential diagnosis is pancreatic cancer. Thus, pancreatic Panobinostat manufacturer cancer diagnosed as AIP or vice versa can conceivably delay therapy for potentially-curable cancer or lead to unnecessary surgery. Thus, it is important to consider a few salient facts when diagnosing AIP. First, pancreatic

cancer is far more common, and second, the gold standard to diagnose AIP is histology.6,16,32 The presence of more than 10 IgG4-positive cells/high power field, along with other feature of AIP, that is LPSP or the presence of GEL, is diagnostic of AIP (see Histology). As obtaining pancreatic tissue for histology often involves invasive procedures (EUS-guided biopsy or pancreatic resection), the need for less invasive surrogates was realized. This led to the evolution of diagnostic criteria for AIP that try to limit pancreatic tissue sampling to only the most challenging cases. In addition, the exquisite sensitivity of AIP to steroid therapy is such

that in select situations, this response to therapy can itself be diagnostic. That said, the use of an empirical trial of corticosteroid therapy to diagnose AIP should be reserved for select situations with careful monitoring, and is strongly discouraged in the presence of features suggestive of pancreatic cancer. Selleck MAPK Inhibitor Library In 2002, the Japan Pancreas Society devised the first diagnostic criteria for AIP, and these were modified in 2006.33,34 The early emphasis was not to miss cases of resectable pancreatic cancer rather than to positively diagnose AIP. Since that time, a plethora of diagnostic criteria have been proposed. They

include the Italian criteria (2003 and 2009), the Mayo clinic HISORt criteria (Histology, Imaging, Serology, Other Organ Involvement and Response to Therapy 2006), the Korean criteria (2007), Asian Consensus criteria (2008), and the International Consensus criteria (2011).6,16,35Table 1 illustrates the HISORt criteria. Despite the numerous sets of diagnostic criteria for AIP, until recently, there have been no established algorithms to help differentiate AIP from pancreatic cancer. We recently published such an algorithm in an attempt selleck products to allow clinicians to select the various diagnostic tools available to differentiate AIP from pancreatic cancer (Table S2).36,37 Once the diagnosis of AIP has been established, corticosteroids are the mainstay of therapy. Recent studies have shown that corticosteroid therapy favorably alters the natural history of AIP; it hastens recovery, decreases complications, and improves symptoms.38,39 There are numerous dosing strategies, and to date, there have been no head-to-head comparisons between these. In our practice, we start with 40 mg/day prednisone orally for 1 month.