Various symptoms emerge as immune-related adverse events of immune checkpoint inhibitor (ICI). A 73-year-old woman, a non-smoker, receiving chemotherapy including atezolizumab for lung adenocarcinoma, presented with fever, bilateral parotid swelling and sicca syndrome after four courses of chemotherapy. Because the lesions were not localized, the diagnosis was ICI-related sialadenitis rather than infectious. Prednisolone improved salivary gland swelling quickly. Six months after the last administration of ICI, there was no obvious progression of lung cancer. To our knowledge, this is the first case of sialadenitis caused by atezolizumab. ICI-related sialadenitis may be a good prognostic marker for lung cancer.

A case of sialadenitis observed as an irAE of atezolizumab: a case report