PMC6542945_01
Muscle MRI findings in Case 1. (a) Axial images of STIR MRI sequences through the upper and lower legs show subtle signal change in the right medial thigh, which had been attributed to the patient's muscle biopsy a few days prior. Otherwise, no abnormality was identified on this study. (b) Axial images of T1 MRI sequences through the upper and lower legs show no abnormality.
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F1
MRI (1.5T) of the leg muscles was acquired in coronal and axial planes with T1 and STIR sequences, from the top of the iliac crests to the ankles bilaterally, and was interpreted as unremarkable (Figure 1).
Muscle pathology findings in Case 1. (a) H&E-FFPE (400x) showing non-rimmed vacuoles; (b) Gomori-trichrome (600x) with non-rimmed vacuoles; (c) Toluidine blue semi thin sections (400x) with empty vacuoles; (d) electron micrograph (1,000x) showing empty vacuoles and Z-line disarray.
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F2
Muscle biopsy showed a vacuolar myopathy confirming the clinical suspicion of colchicine myopathy (Figure 2).
PMC6542945_02
Muscle pathology findings in Case 2. (a) H&E-frozen (40X) showing rare rimmed vacuoles and increased internal nucleation, (b) Gomori trichrome (100X) highlights granular material of the typical rimmed vacuole, (c) ATPase pH4.3 (100X) shows vacuoles to have a predilection for Type I fibers, and (d) Electron microscopy (10,000X) demonstrates autophagic vacuoles.
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F3
MRI of the lumbar spine did not show any changes that would explain his weakness but did indicate degenerative disc disease particularly at the L3-5 levels. Muscle biopsy revealed vacuolar myopathy characterized by type I-specific central rimmed vacuoles that were reactive to acid phosphatase and immunoreactive to alpha-B-crystallin (Figure 3).