What is the typical appearance of the calves in DMD, and what causes it?

• A. Calf swelling due to edema
• B. Calf pseudohypertrophy due to edema
• C. Calf atrophy with fat deposition
• D. Calf pseudohypertrophy due to fat and fibrous tissue replacing muscle

Answer: (D)

In Duchenne muscular dystrophy, the calves often look enlarged not because the muscle is gaining real bulk, but because muscle fibers are progressively destroyed and replaced by fat and fibrous tissue. This creates a firm, enlarged appearance known as pseudohypertrophy, while the muscle becomes weaker.

This is the best choice because it captures both the appearance (calf enlargement) and the underlying cause (fat and fibrous tissue replacing muscle fibers). It’s not edema, which would be fluid-driven swelling, nor true hypertrophy or atrophy with fat deposition alone—the defining feature is noncontractile tissue overtaking muscle, producing a pseudohypertrophied calf.