Fullam et al.

Confidential. © 2021 American Academy of Neurology 1

Resident & Fellow Section Teaching NeuroImage

58-year-old male with metastatic melanoma (in

remission) presented with pain, limited joint mobility, and proximal weakness

Fullam et al.

Confidential. © 2021 American Academy of Neurology 2

Vignette

58-year-old man with metastatic melanoma, previously treated with ipilimumab and nivolumab, presented with pain, limited joint mobility and proximal weakness

There was no oculobulbar weakness, dyspnea, or rash.

EMG demonstrated positive sharp waves, fibrillations and myopathic units.

Extremity MRI demonstrated diffuse fascial and mild muscle enhancement consistent with fasciitis/mild myositis.

Creatinine kinase was normal (though checked after 2 rounds of high-dose corticosteroids).

PET-CT obtained prior to consultation showed diffusely FDG-avid lymph nodes, skeletal muscles and overlying soft tissues.

Though initially concerning for relapsed melanoma, lymph node biopsy instead showed noncaseating granulomatous changes concerning for sarcoid-like granulomas as can be see with ICI-related inflammatory reactions

Fullam et al

^.

Confidential. © 2021 American Academy of Neurology 3

Imaging

Fullam et al.

Confidential. © 2021 American Academy of Neurology 4

Immune Checkpoint Inhibitor–Related Fasciitis and Myositis With Perifascicular Atrophy

 Histopathology of immune checkpoint inhibitors (ICI)-related myositis was initially characterized by necrosis with

macrophages/T-cell infiltrates.

 The spectrum has expanded to include perimysial/perivascular inflammatory infiltrates and a tendency towards perifascicular atrophy, as seen in our case.

 Immunotherapy has been initiated and is ongoing.

Fullam et al.