Pembrolizumab-Induced Pancreatic Exocrine Insufficiency Complicated by Severe Hepatic Steatosis

Abstract

Anti-programmed death receptor-1 (anti-PD-1) monoclonal antibodies (mAbs) are used to treat an increasing range of cancers. However, the distinct toxicity profile of immune-related adverse events (irAEs) is a frequent drawback of their clinical application. Among the more common irAEs are hepatitis and colitis, which are diagnosed and graded in patients based on elevated serum liver enzyme levels and increased stool frequency, respectively, and both of which often require treatment with high-dose corticosteroids. Herein, we describe the case of a patient who developed severe transaminase elevation and diarrhoea due to an unusual irAE, which was successfully treated without corticosteroids.

Keywords: hepatic steatosis; immune-related adverse event; immunotherapy; pancreatic exocrine insufficiency; pembrolizumab.

Figure 1. Abdominal CT scan performed in January 2019 (A) and October 2019 (B), respectively.

(A) The liver demonstrates a homogenous reduction in density, in keeping with hepatic steatosis. No focal liver lesion is demonstrated on this background. (B) Resolution of hepatic steatosis and an increase in subcutaneous fat following successful treatment of PEI. CT: computerised tomography; PEI: pancreatic exocrine insufficiency.

Figure 2. Liver biopsy findings.

The results of the liver biopsy revealed a bland, but diffuse and severe steatosis, without features of an immunotherapy-related hepatitis or of fibrosis.