Background: Autoimmune pancreatitis (AIP) and IgG4-related cholangitis (IRC) are newly-recognized diseases. Reports in Thailand are scarce.
Objective: To evaluate clinical presentations, other organ involvement (OOI), serology, radiologic, endoscopic features and treatment of AIP and IRC in one institute.
Materials and Methods: Patients with AIP and IRC, who were diagnosed and followed-up at Siriraj Hospital during 2005 to 2016 were retrospectively reviewed.
Results: There were 15 patients (75%) with AIP, 7 patients (37%) with IRC (4 isolated IRC and 3 IRC with AIP) and 1 (5%) with IgG4-related disease without AIP or IRC (sialadenitis and retroperitoneal fibrosis). Male to female ratio was 1.9: 1. Median age of onset was 64 years. Among the 15 AIP, all were type 1. Initial presentations were jaundice (60%), abdominal pain (40%), OOI (20%; sialadenitis, orbital pseudotumor), and weight loss (7%). Clinical manifestations during the course were jaundice (80%), abdominal pain (67%), weight loss (47%), OOI (47%; retroperitoneal fibrosis, IRC, sialadenitis, orbital pseudotumor, periurethral mass, lung nodules) and steatorrhea (7%). Serum IgG4 was elevated in all patients. Radiography showed diffuse type in 8 cases (53%), focal type in 5 (33%), and unknown in 2 (13%). More than half were suspicious of AIP before diagnosis. Corticosteroid was required in 10 patients (67%). Maintenance therapy was offered in 5 patients (33%) with steroid and azathioprine. Surgery was performed before diagnosis in 7 patients (47%). Spontaneous remission occurred in 4 patients (27%). Among the 7 IRC, initial presentations were jaundice (57%), weight loss (29%), abdominal pain (14%), prolonged fever (14%), and cholangitis (14%). Clinical manifestations during the course were jaundice (57%), abdominal pain (57%), weight loss (29%), recurrent cholangitis (14%) and retroperitoneal fibrosis (14%). Serum IgG4 was elevated in 5 patients (71%). Prednisolone was prescribed in 6 cases (86%). Five patients (71%) required azathioprine. Surgery was performed before diagnosis in 4 patients (57%).
Conclusion: AIP and IRC were uncommon. The most common presentation was jaundice. All AIP were type 1 and more than half were diffuse type. OOI were common. Half of IRC had AIP. Approximately half of AIP/IRC patients underwent surgery before diagnosis. Corticosteroid was mainstay treatment.

Keywords: Autoimmune pancreatitis, IgG4, Immunoglobulin G4, Sclerosing cholangitis, Thailand