PMC10239300_01
(a) Magnetic resonance imaging (MRI) of the shoulder, oblique axial view, DP sequence, with fat saturation, showing hyperintensity in the m. pectoralis major and m. deltoid. (b) MRI of the shoulder, oblique sagittal view, T2 sequence with fat saturation, showing hyperintensity in the rotator cuff muscles (supraspinatus, infraspinatus, and subscapularis). (c) MRI of the pelvis, axial section, and STIR sequence, showing hypersignal in the adductor and extensor muscles of the thigh and in the gluteus maximus. (d) MRI of the pelvis, coronal section, and STIR sequence, showing hyperintensity in the thigh extensor musculature.
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fig1
Magnetic resonance imaging of the shoulder and pelvic girdles was performed, which showed diffuse edema of the musculature (Figure 1).
(a) Hematoxylin and eosin analysis shows angular and rounded atrophic fibers, diffuse inflammatory reaction, foci of fiber necrosis, and phagocytosis of necrotic fibers. (b and c) Transmission electron microscopy analysis reveals variation in fiber caliber, presence of necrotic fibers, autophagic voids of emissions filled with dense granules and membrane remnants, subsarcolemmal occurrences of mitochondria, and perivascular and endomysial inflammatory infiltrates.
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fig2
Taken together, these findings are suggestive of IMNM (Figure 2).