RESUMEN
Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy over the last decade. Pembrolizumab, a humanized monoclonal IgG4 antibody, binds to the programmed death 1 (PD-1) receptor, blocking its interaction with programmed death-ligand 1 (PD-L1) and thereby increasing the anti-tumor activity of the host immune system. These drugs are associated with immune-mediated side effects that can be life threatening, and myocarditis is among the most serious events. We present a 48-year-old woman with a history of progressive thymoma who developed complete atrioventricular block associated with fulminant myocarditis and myasthenia gravis 2 weeks after starting treatment with pembrolizumab. She had also presented a couple of days before to the emergency department due to dyspnea that was related to pleural effusion. Electrocardiogram (ECG) and echocardiogram were unremarkable, but she had very mildly increased troponin levels that were attributed to acute respiratory compromise, so she was discharged after successful thoracentesis. Despite aggressive treatment combination of high-dose corticosteroids, immunosuppressive agents and anti-thymocyte globulin, the disease rapidly progressed to the fatal outcome. This report remarks on the importance of rapid consideration of ICI-induced myocarditis even if cardiac biomarkers are slightly elevated, as a mild presentation can go unnoticed and progress to a severe case. Therefore, a high index of suspicion is warranted in these patients and cardiac imaging techniques such as magnetic resonance could have a role diagnosing incipient cardiac inflammation.
RESUMEN
Primary brain lymphoma is a rare variant of extranodal non-Hodgkin's B-cell lymphoma. In >90% of cases, this is diffuse large B-cell lymphoma with CD20 expression and is confined to the brain, meninges, spinal cord, and eyes. It accounts for fewer than 7% of primary brain tumors. Its incidence has been rising in recent years in immunocompetent patients in their fifth and sixth decades. The rate of relapse after initial therapy based on high-dose methotrexate and/or total brain irradiation is high. There is no consensus for treating relapse, which ranges from retreatment with high doses of methotrexate, polychemotherapy, high doses of chemotherapy backed up by autologous stem-cell transplant to intrathecal chemotherapy, with widely differing results. Given the lack of consensus and poor results, new therapy options have appeared, including immunotherapy with rituximab. At a systemic level, alongside chemotherapy, its results are very modest and limited due to the low concentration it reaches in cerebrospinal fluid (CSF). However, its intrathecal and intraventricular use, though only isolated cases have been reported, has provided promising results.
