A case of durvalumab-induced lichenoid eruption evolving to bullous eruption after phototherapy: A case report.

Immune checkpoint inhibitor therapy nowadays became a treatment for a wide range of cancers, and may be responsible for various dermatologic adverse effects, including bullous eruptions. In our report, we present a case of late-onset immunotherapy-induced eruption in a 62-year-old woman treated with anti-programmed cell death-L1 agent durvalumab for metastatic squamous cell carcinoma. Diagnosed as lichenoid dermatitis upon initial presentation, this eruption evolved into necrotic bullous dermatitis after several weeks of phototherapy, with histology and direct immunofluorescence study favoring lichen planus pemphigoides. Thus, this case may be regarded as durvalumab-induced lichenoid dermatitis with phototherapy-triggered progression to necrotic lichen planus pemphigoides-like eruption. The patient's eruption responded to oral prednisone and immunotherapy interruption. Interestingly, durvalumab reintroduction in this patient led to recurrent lichenoid dermatitis without bullous component. This case of immunotherapy skin toxicity is rather distinctive by its clinical and histopathologic features, with phototherapy as an additional triggering factor.