Case of simultaneous occurrence of hepatitis, cholangitis, and pancreatitis as immune-related adverse events induced by immune checkpoint inhibitor therapy: a case report.

The use of immune checkpoint inhibitors has increased in the field of oncology; however, various immune-related adverse events affecting multiple organs have been reported. Herein, we present a case of concurrent hepatitis, cholangitis, and pancreatitis as immune-related adverse events (irAE); a case of autoimmune disease due to oncologic immunotherapy. A man in his 80s who was undergoing pembrolizumab therapy for recurrent renal pelvic cancer presented to the emergency department with a loss of appetite. Laboratory tests revealed elevated levels of inflammatory markers and liver enzymes. Initial non-contrast computed tomography (CT) suggested cholecystitis and cholangitis, for which antibiotics were administered. However, because of poor improvement, contrast-enhanced dynamic CT and gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid-enhanced magnetic resonance imaging (MRI) were performed two weeks after visiting the emergency department to reassess the underlying cause. In these examinations, besides the bile dust wall thickening and edematous changes along Glisson's sheath suggesting the cholangitis, inflammatory enlargement in pancreatic tail was also revealed. Considering these imaging findings suggesting the cholangitis and pancreatitis during pembrolizumab therapy, irAE was suspected as the cause of symptoms. A liver biopsy subsequently performed strongly indicated hepatitis and cholangitis as irAE. Based on these findings, concurrent hepatitis, cholangitis, and pancreatitis as irAE by pembrolizumab were diagnosed. Imaging findings of irAE cholangitis are similar to those of primary sclerosing cholangitis and IgG4-related cholangitis. Particularly in cases like this one, where pancreatitis is also present. However, if a history of immune checkpoint inhibitor use is known, it is possible to include irAE in the differential diagnosis, as observed in this case. Therefore, by keeping the use of immune checkpoint inhibitors in mind during imaging interpretation, imaging examinations could be a clue to suggest the possibility of irAE. Recognizing the imaging findings associated with irAEs and the existence of cases where irAE cholangitis and irAE pancreatitis coexist, it can aid earlier diagnosis of irAEs.