Fig. 2.

A 44-year-old male with incidental positive COVID-19 test obtained prior to eye surgery. He did not have any respiratory symptoms and was surprised by the positive test. In the following 2–3 weeks, he developed progressive weakness and swelling requiring hospitalization. MR imaging of the upper and lower extremities with intravenous contrast was performed. a Axial T2-weighted fat-saturated and b axial post-contrast T1-weighted fat-saturated images demonstrate diffuse edema and enhancement of the proximal right upper extremity musculature (arrows). c Coronal T2-weighted fat-saturated image of the left lower extremity demonstrates muscle edema of the proximal muscles/limb girdle (arrow) with sparing of the distal muscles. Subcutaneous soft tissue edema is noted. Biopsy of the deltoid muscle was performed. d Histopathologic findings included scattered pale degenerating myofibers, surrounded by macrophages (arrow) on H&E stain. e Acid phosphatase highlighted the macrophages (arrow). f NADH stain showed an unusual ring-like pattern to the myofibrillar architecture (scale bar = 100 μm). The patient was diagnosed with post-infectious inflammatory necrotizing myositis and discharged on oral prednisone with subsequent clinical improvement and decrease in CK levels on follow-up