PMC6169218_01
[18F] Fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT). (a) Whole-body scan showing increased uptake in the proximal aspect of all limbs. (b) Proximal lower limbs that show a standardized uptake value (SUV) of 1.8 g/ml (left) and 1.6 g/ml (right); upper limb SUVs were 1.6 g/ml (left) and 1.1 g/ml (right). (c) Liver shows a more pronounced FDG uptake than all limbs with an SUV of 3.2 g/ml. (d) Mediastinal vessels were also with a more significant uptake compared to all limbs, with an SUV of 2.1 g/ml. (a-d) Areas with increased SUV signaled with white arrows.
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fig1
An FDG-PET/CT scan was performed searching for neoplasia due to the patient's past history and revealed increased FDG uptake in bilateral quadriceps, without posterior compartment muscle uptake or increased metabolism in any other region of the body (Figure 1).
Left proximal and distal quadriceps muscle biopsy. Mild lymphohistiocytic myositis by CD8+ T cells, with severe myonecrosis (50%). The muscle fibers are healthy appearing, with some affected areas characterized by myonecrosis, phagocytosis by CD68+ cells (macrophages), and regeneration. There is no vasculitis, granulomas, eosinophilia, or thrombosis. (a) CD8+ T cell infiltrate (Gomori trichrome stain) (white arrow). (b) CD 68+ cell infiltrate (hematoxylin and eosin stain) (black arrow).
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fig2
There were no immune deposits in the skin microscopic examination (Figure 2).