Checkpoint Inhibitor-associated Cutaneous Small Vessel Vasculitis: A Review of the Literature

Immune checkpoint inhibitor-induced cutaneous toxicities: a review of histopathologic and clinical features

Immune checkpoint inhibitors (ICIs) represent an emerging treatment option for a variety of cancer types. Through inhibition of programmed cell death protein 1 (PD-1), programmed cell death ligand 1 (PD-L1), and/or cytotoxic lymphocyte-associated antigen-4 (CTLA-4), ICIs activate the host's immune system causing a heightened anti-tumor response. However, off-target effects of ICIs can result in numerous different immune-related cutaneous adverse events (irCAEs). Beyond impacting quality of life, irCAEs can lead to dose limitations or discontinuation of anti-cancer therapies. Correct diagnosis is necessary for expedient and appropriate management. Skin biopsies are often performed to increase diagnostic accuracy and guide clinical management. An extensive literature review was performed using the PubMed database to identify the reported clinical and histopathologic features of irCAEs. This comprehensive review primarily details the histopathologic features of various irCAEs reported to date. Clinical presentation and immunopathogenesis are also discussed in relation to histopathology.

Cutaneous vasculitis associated with molecular tergeted therapies: systematic review of the literature

Cutaneo us vasculitis (CV) has a broad spectrum of etiologies, and drugs are one of the main culprits. With the increasing use of targeted therapies in medicine, especially in rheumatology and oncology, the number of CV cases reported due to these drugs has increased. Therefore, the recognition and treatment of CV associated with targeted agents have become more and more important. In the literature, anti-TNFs (n = 73, 59.5%), secukinumab (n = 7, 6%), rituximab (n = 5, 4%), tocilizumab (n = 1, 0.8%), ustekinumab (n = 8, 6.5%), abatacept (n = 3, 2.4%), Janus kinase inhibitors (n = 3, 2.4%), alemtuzumab (n = 3, 2.4%), and immune checkpoint inhibitors (n = 20, 16%) have been reported as responsible agents. However, our knowledge of the pathogenetic mechanisms is fairly limited, and the standardized management is yet to be established. Furthermore, though it is uncommon, this complication may pose a safety issue. In this manuscript, we reviewed the literature on CV with or without systemic involvement related to targeted agents. We also proposed the pathogenetic mechanisms of these adverse events. Thus, we aimed to make it easier for clinicians to manage similar cases by reviewing the diagnosis and treatment processes.