Cutaneous reactions to modern systemic oncologic therapies: a histopathological and clinical review

Modern oncologic treatments such as antibody‐drug conjugates, targeted therapies, CAR‐T‐cell therapies and immune checkpoint inhibitors show improved efficacy through novel mechanisms of action when compared to conventional chemotherapy. However, these agents are often associated with cutaneous adverse events, many of them with distinctive clinical and histopathological patterns. Such events may be severe, impairing quality of life and sometimes leading to interruption of critical cancer treatment. As the use of these therapies continues to expand, dermatologists and dermatopathologists will increasingly encounter their associated toxicities. Recognition of histopathological patterns enables an accurate diagnosis and guides clinical management. Herein, we review the main cutaneous adverse events associated with antibody‐drug conjugates, targeted therapies, CAR‐T cell therapies and immune checkpoint inhibitors, summarizing clinical features and emphasizing histopathological findings.