Abstract
We report a patient with malignant pleural mesothelioma who developed pancreatic enzyme elevations and pancreatitis during immune checkpoint inhibitor treatment. A male in his eighties visited his family clinic because of respiratory distress on exertion and was pointed out a left pleural effusion. A thoracoscopic pleural biopsy gave a diagnosis of desmoplastic pleural mesothelioma. The patient was started a combination immunotherapy of ipilimumab and nivolumab. At a routine visit of 32 days after the start of the treatment, blood tests revealed elevated amylase and lipase. The patient had no subjective symptoms such as abdominal or back pain or loss of appetite. Contrast-enhanced computed tomography imaging revealed decreased contrast uptake in the pancreas, and magnetic resonance imaging revealed edematous changes in the pancreas. These findings led us to the diagnosis of asymptomatic immune mediated acute pancreatitis. Extracellular fluid replacement and steroid treatment were initiated. Both amylase and lipase quickly decreased close to normal range but began to rise again when the prednisolone dose was reduced. Infliximab was administered, then amylase and lipase decreased again. Follow-up magnetic resonance imaging demonstrated that the edematous changes in the pancreas had resolved. During the treatment of pancreatitis, mesothelioma demonstrated no exacerbation. There is no established treatment strategy for immune mediated pancreatitis. Appropriated management of asymptomatic elevation of pancreatic enzymes during ICI treatment should be established.