Interstitial Pneumonitis in a Patient with Occult Sarcoidosi
A case that highlights the prompt recognition and management of immune-related adverse events associated with immune checkpoint inhibitors used in the management of solid tumours.

Case Report

- A 68-year-old man was started on pembrolizumab for the management of metastatic melanoma. No BRAF mutation was identified on tumour mutational analysis but he was found to have rare c-KIT mutations (exon 11 mutation c.1733A>G [Y578C] and exon 17 c.2447A>T [D816V]). Computed tomography (CT) staging onemonth prior had found hypermetabolic skin lesions in the torso, ground glass changes in lung fields with mediastinum and hilar lymphadenopathy, in keeping with stage II sarcoidosis (Figure 1a). He did not have any previous diagnosis of sarcoidosis...