Decoding follicular cholangitis: A benign entity with a malignant façade

Follicular cholangitis (FC) is a rare, benign inflammatory biliary disorder that can closely mimic malignancy. We present the case of a 34-year-old lady with an incidentally detected distal common bile duct (CBD) lesion. Preoperative imaging was suggestive of periampullary malignancy. However, serology and biopsy findings were inconclusive. Intraoperative frozen section analysis revealed cholangitis with prominent lymphoid aggregates, ruling out malignancy. These critical intraoperative histopathological findings guided toward a conservative surgical approach in the form of antegrade CBD excision with ampullectomy. Histopathology confirmed the diagnosis of FC and excluded differentials such as IgG4-related sclerosing cholangitis and primary sclerosing cholangitis (PSC). This case underscores the importance of frozen section analysis in distinguishing FC from malignancy, allowing for a tailored surgical strategy that minimizes unnecessary extensive resection and morbidity. Increased awareness of FC among clinicians is essential to prevent overtreatment, emphasizing the importance of integrating histopathologic, radiologic, and clinical findings for accurate diagnosis and management.