Figure 3. Muscle imaging of lower limbs.

All cases demonstrate a distinctive feature of diffuse involvement of the quadriceps muscles and relative sparing of the adductor compartments with relative hypertrophy of the adductor longus (single white arrow) and of the semitendinosus muscle (black arrow) at the thigh level, while at the calf level there was diffuse involvement (double white arrow) with sparing of the anterior-medial muscles. Cases SW2.I and NL1.I show a milder pattern of involvement at the calf level but with relative sparing of the medial-anterior compartment.