Surgery in Autoimmune Pancreatitis.

Introduction: Autoimmune pancreatitis (AIP) is a disease that may mimic malignant pancreatic lesions both in terms of symptomatology and imaging appearance. The aim of the present study is to analyze experiences of surgery in patients with AIP in one of the largest European cohorts.

Patients and methods: We performed a single-center retrospective study of patients diagnosed with AIP at the Department of Abdominal Diseases at Karolinska University Hospital in Stockholm, Sweden, between January 2001 and October 2020.

Results: There were 159 patients diagnosed with AIP, and among them, 35 (22.0%) patients had surgery: 20 (57.1%) males and 15 (42.9%) females; median age at surgery was 59 years (range 37-81). Median follow-up period after surgery was 50 months (range 1-235). AIP type 1 was diagnosed in 28 (80%) patients and AIP type 2 in 7 (20%) patients. Malignant and premalignant lesions were diagnosed in 8 (22.9%) patients for whom AIP was not the primary differential diagnosis, but in all cases, it was described as a simultaneous finding and recorded in retrospective analysis in histological reports of surgical specimens.

Conclusions: Diagnosis of AIP is not always straightforward, and in some cases, it is not easy to differentiate it from the malignancy. Surgery is generally not indicated for AIP but might be considered in patients when suspicion of malignant/premalignant lesions cannot be excluded after complete diagnostic workup.