PMC7362278_01
MRI of right forearm: diffuse hyperintensity of the forearm flexor muscles, including the superficial and deep compartments, extending along the corresponding myotendinous joints with intense muscle uptake of gadolinium.
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The magnetic resonance imaging (MRI) of the right forearm (Fig. 1) revealed signs of inflammation in the superficial and deep flexor muscles of the forearm, suggesting myositis.
Muscle biopsy of flexor muscle of forearm: extensive fibrosis and an inflammatory process involving the endomysium, perimysium and fascia, with macrophages towels, some lymphocytes and perivascular plasma cells, not identifying granulomas (A). The immunohistochemical test was strongly positive for CD68 (B).
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A muscle biopsy was performed in the flexor compartment of the right forearm (Fig. 2), which showed extensive fibrosis and an inflammatory process involving the endomysium, perimysium and fascia, with macrophages towels (Figs. 2A and 2B).