GÉTICA 2021

31 [ F I T C á n c e r - 7 ] CC08. TREATMENT-RELATED HEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS DUE TO ATEZOLIZUMAB: A CASE REPORT AND REVIEWOF THE LITERATURE Rodríguez-Pérez, Ángel 1 ; Rubio-Pérez, Jaime 2 ; Díaz Blázquez, María 3 ; Moreno, Víctor 3 ; Domine, Manuel 1 1 Medical Oncology Department, 2 Anatomic Pathology Unit Department, 3 START Madrid-FJD. Hospital Universitario Fundación Jiménez Díaz. Madrid Background: Immune checkpoint inhibi- tors (ICI) avoid inhibition of T-cell responses, up-regulating anti-tumour immune response. As a secondary effect, dysregulation with hy- peractive immune response can be caused as a systemic immune-related adverse event. Hemophagocytic Lymphohistiocytosis (HLH) is a rare and often fatal syndrome of uncon- trolled and ineffective hyperinflammatory response that triggers an inflammatory cas- cade that can lead in many cases to death (1). A major part of them is underdiagnosed, but early diagnosis is the key of the treatment in most of them (2). We present a case of a 67-year-old man with a stage IV adenocarcinoma of the lung that de- veloped an HLH after receiving the first dose of atezolizumab, as second-line therapy. Being the first case described in the literature, with the use of this new agent. He was consulted due to intense fever and dyspnea. The next 24 hours he started with vomiting and drowsi- ness, so he was admitted to the intensive care unit and intubated. After excluding infection, and pulmonary complications, he fulfilled most of the clinical criteria that have been described to identify HLH. The HScore for the hemophago- cytic syndrome was 256 points (> 99 % proba- bility). Given the high suspicion treatment with 1.5 mg/kg, dose corticosteroids were initiated, and confirmation obtained with bone marrow biopsy (Fig. 1). After 3 days without change and severe pancytopenia despite transfusions, we followed the latest recommendations giving tocilizumab at 8 mg/kg without success so we continued with anakinra without analytical or neurological improvement. Treatment with my- cophenolate mofetil was added for the next two days and finally, 5 days after admission, etopo- side 100 mg/m 2 . MRI was performed showing extensive white matter damage (Fig. 2). An elec- troencephalogram exhibited diffuse and severe degree brain involvement. Hence, it was decid- ed to limit the therapeutic effort. Necropsy of Figure 1.