Figure 1.

Sarcoidosis-like reaction to immunotherapy. ((a,d), left panels) Axial FDG PET-CT scan of the head (a) demonstrates a hypermetabolic mass (melanoma) invading the right temporalis muscle with lateral intra-orbital extension (white arrow). (d) No mediastinal adenopathy is present on axial FDG PET-CT of the upper chest. ((b,e), middle panels) Follow-up FDG PET scan while on immunotherapy. (b) Axial FDG PET-CT scan of the head demonstration that the melanoma in the right temporalis muscle is stable (white arrow). (e) Axial FDG PET-CT during immunotherapy demonstrates new hypermetabolic bilateral hilar and subcarinal adenopathy (white arrowheads), that was granulomatous on biopsy; ((c,f), right panels) Follow-up FDG PET-CT following discontinuation of immunotherapy shows stable melanoma ((c), white arrow) and resolution of hypermetabolic mediastinal and hilar adenopathy (f).