Pembrolizumab Induced Hypophysitis in a Patient Allergic to Triamcinolone: An Increasingly Recognized Endocrinopathy Related to Immunotherapy.

We would like to describe the clinical course of a 61-year-old gentleman with the background history of Stage IV left lower lobe lung adenocarcinoma who presented to the outpatient department at Changi General Hospital, Singapore on March 2019 with unintentional loss of weight, easy fatigability and breast pain while showering for last four months. He was started on pembrolizumab immunotherapy about 9 months before presentation which he tolerated well. Subsequent endocrine work ups revealed features consistent with hypophysitis that lead to hypopituitarism in the form of secondary adrenal insufficiency and hypothyroidism. While more and more patients are receiving novel anti-cancer treatment for example immunotherapy, we should never forget and address the side effects it brings along. This study certainly supports above mentioned suggestion.