Destroyed lung due to sustained inflammation after chemoradiotherapy followed by durvalumab

A 68-year-old male patient with squamous cell carcinoma (cT4N2M0) of the left upper lobe received chemoradiotherapy followed by durvalumab, an immune checkpoint inhibitor. The tumour responded well to the therapy, but an infiltrative shadow appeared in the left upper lobe, which was outside the radiation field. Despite treatment with corticosteroid and antibiotics, the development of a cavitary lesion was noted. As Aspergillus fumigatus was isolated from the bronchoscopy specimen, antifungal agents were also administered, but the cavitary lesion further developed. Because his general condition worsened and the entire left lung was destroyed, the patient underwent a left pneumonectomy and recovered without recurrence. The pathology of the removed lung revealed a scarred nodule with granulation tissue around and a cavernous lesion having a necrotic substance inside. We considered that durvalumab might further accelerate the inflammatory response, which had been introduced by fungal infection, leading to uncontrollable inflammation of the lung.