Ipilimumab-Induced Adrenalitis: A Possible Pitfall in 18F-FDG-PET/CT.

Ipilimumab is a monoclonal antibody against the inhibitory CTLA-4 receptor expressed on T cells. It provokes an upregulation of the immune system. This substance was approved by the US Food and Drug Administration in 2011 and is since increasingly used as a targeted therapeutic approach for metastasized melanoma. Ipilimumab is known to cause neuroendocrine disorders, such as hypophysitis and adrenal insufficiency. Our case of a 79-year-old patient represents an important imaging pitfall. Imaging findings of newly symmetrically and smoothly enlarged, hypermetabolic adrenal glands in the setting of previous ipilimumab therapy represent drug-induced adrenalitis and not metastatic disease.