Presentation
Bronchial carcinoma PD-L1+ in the right upper lobe treated with radiotherapy and chemotherapy then with immunotherapy (durvalumab).
Patient Data
Onset: 6 mth after initiation of durvalumab
Bilateral GGO forming circles, creating the "reversed halo" or "atoll" signs suggesting an organising pneumonia pattern.
GGO with similar OP pattern, non migratory, but fading compared to previous CT.
Emerging peripheral subpleural reticulations and GGO, asymmetrically, with left predominance, and traction bronchiectasis.
In some areas, there is a subpleural thin line of spared lung parenchyma typical of the fibrotic NSIP pattern.
Case Discussion
This is a case of immune checkpoint inhibitor therapy-related pneumonitis with durvalumab, an anti-PD-L1 binding human monoclonal antibody, which allows T lymphocyte activation and cytotoxic function towards tumours expressing PD-L1 surface protein.
At the onset of the pneumonitis, the atoll / reversed halo signs were highly suggestive of organised pneumonia pattern. BAL was not performed although it would have been advised to do so to rule out mucormycosis-related pneumonia, which also features atoll / reversed halo signs.
Upon follow-up, the patient developed an NSIP pattern.