Eosinophilic cholangitis: A case report of diagnostically challenging eosinophilic infiltrative biliary obstruction

BACKGROUND Evaluation of biliary strictures primarily focuses on ruling out malignancy in older age groups. With endoscopic tools such as endoscopic ultrasound(EUS)and cholangioscopy, improved biliary visualization has enhanced the investigation of intraluminal biliary lesions and provided modalities for targeted biopsies. Benign biliary strictures, however, may pose a diagnostic dilemma.CASE SUMMARY A 71-year-old female with past medial history of hypothyroidism presenting for abnormal biliary imaging. Patient's previous evaluation was concerning for common bile duct dilation with cholelithiasis, for which she underwent a cholecystectomy. Due to persistent symptoms and worsening liver function tests,she presented to our institution for further workup. Subsequently, the patient underwent an EUS and multiple ERCP's with cholangioscopy; biliary biopsies revealed no evidence of malignancy but concerning for prominent eosinophilic infiltration. After further review of multiple pathology specimens and the benign clinical course, we diagnosed the patient with eosinophilic cholangitis.CONCLUSION Eosinophilic cholangitis is a rare disease and can present as a challenging case diagnostically. This case raises the potential utility of quantitative eosinophilic infiltration reporting in creating an objective diagnostic metric for eosinophilic cholangitis.