49-year-old female with weakness. Evaluate for muscle disease Left femur: There is severe fatty replacement of the visualized gluteal musculature with near complete fatty replacement of the gluteus minimus and medius muscles. There is also near complete fatty replacement of the visualized distal iliopsoas muscle. There is near complete fatty replacement of the adductor and hamstring muscle groups as well as the rectus femoris and sartorius muscles. There is moderate fatty atrophy of the vastus intermedius and relatively mild fatty atrophy of the vastus medialis and lateralis muscles. We see no edema within any of the muscles to indicate an active myositis. Bone marrow signal intensity of the left femur is within normal limits with the exception of a 1 cm lobulated focus of signal abnormality within the intertrochanteric region which likely represents a benign enchondroma. Moderate osteoarthritis affects the left knee. Small knee joint effusion. Similar fatty infiltration of the muscles of the right thigh is seen on the large field-of-view images.Left Humerus: There is near complete fatty replacement of the muscles of the entire arm as well as much of the visualized anterior compartment of the forearm muscles. There is complete fatty replacement of the anterior aspect of the deltoid muscle with less prominent atrophy posteriorly. There is complete fatty replacement of the subscapularis muscle, severe fatty atrophy of the infraspinatus muscle and relatively mild fatty atrophy of the supraspinatus and teres minor muscles. There is also profound fatty replacement of the visualized pectoralis major, latissimus dorsi, and teres major muscles. We see no edema within any of the muscles to indicate an active myositis. There is prominent red marrow within the proximal humerus but we see no focal lesions.
Profound fatty replacement of the muscles of the left thigh and left arm.