Vasculitic Neuropathy Associated with Pembrolizumab

Immune-related neuromuscular complications due to immune checkpoint inhibitors (ICIs) are widely reported. However, cases involving vasculitic neuropathy (VN) are rare. We report a case of pembrolizumab-associated VN, confirmed by nerve biopsy, presenting as mononeuritis multiplex with erythematous skin lesions. Based on negative serological tests for other causes of vasculitis and temporal relationship with ICI treatment, vasculitis was suspected to be associated with pembrolizumab. VN should be considered in patients with progressive neurological symptoms and skin lesions after receiving ICI therapy.