Eosinophilic cholangitis as an indeterminate biliary mimic: A systematic review of outcomes.

Eosinophilic cholangitis (EC) is a rare inflammatory biliary disorder that can mimic primary sclerosing cholangitis and cholangiocarcinoma. We performed a PRISMA 2020-guided systematic review to summarize diagnostic features, management, and outcomes. Web of Science, PubMed, MEDLINE, Embase, Scopus, and CINAHL were searched; 55 studies (55 patients) were included. Among cases with a preoperative impression (n = 39), malignancy was suspected in 19 (48.7%). Among cases with reported localization (n = 44), isolated extrahepatic disease occurred in 15 (34.1%) and isolated intrahepatic disease in 7 (15.9%). Tissue eosinophilic infiltration was reported in 52/53 (98.1%). Steroids were the primary treatment (35/42, 83.3%), with symptom resolution in 36/37 (97.3%) and biochemical normalization in 39/39 (100%). Serum IgE, when reported, was normal in 4/15 cases by author classification. EC commonly presents as an indeterminate biliary stricture with frequent eosinophilia and is often misdiagnosed as malignancy.