IMMU-54. PNEUMOCYSTIS JIROVECII PNEUMONIA INFECTION IN A PATIENT WITH ANAPLASTIC ASTROCYTOMA AND RADIATION NECROSIS IN THE SETTING OF CORTICOSTEROID AND PEMBROLIZUMAB USE

Abstract

Abstract We present a case with anaplastic astrocytoma and radiation-induced brain necrosis, diagnosed with pneumocystis jirovecii pneumonia(PJP) while receiving corticosteroid and pembrolizumab, an immune checkpoint inhibitor(ICI). ICIs have significantly changed management of many cancer types and are known to be associated with immune related adverse events(irAEs). Recently, concerns have emerged regarding the potential relationship between ICI use and infection risks, and PJP, a rare opportunistic infection, has been reported in patients with ICI treatments with or without corticosteroid use. A 40-year-old man with anaplastic astrocytoma and radiation-induced brain necrosis on corticosteroid and pembrolizumab presented with high fever and tachycardia over three days, and the patient later developed hypoxia and cough. The patient was on dexamethasone for brain radiation necrosis for two months and he received one dose of pembrolizumab two weeks prior to his symptom onset, based on genetic information that showed hypermutated tumor and abnormal DNA mismatch repair protein expression. Chest CT showed abnormal findings from infectious or inflammatory process. Bronchoalveolar lavage sample confirmed positive pneumocystis jiroveci PCR test, confirmed PJP, and he was treated with clindamycin, primaquine, and prednisone. To the best of our knowledge, this is the first reported case of PJP in a patient with primary brain tumor receiving corticosteroid and pembrolizumab. ICIs are being investigated in patients with primary brain tumors and wildly used in patients with malignancies with frequent central nervous system involvements, such as malignant melanomas and non-small cell lung cancers. Awareness of risk for infectious conditions including PJP in patients on ICI treatment, especially with corticosteroid use is crucial for implementing appropriate prophylactic measures and prompt diagnosis and treatment interventions.