Histologically, DMD is characterized by the following key features:
Muscle Fiber Necrosis: Early stages show muscle fiber necrosis and regeneration, with the presence of necrotic fibers that are infiltrated by macrophages. Fibrosis and Fatty Infiltration: As the disease progresses, muscle tissue is replaced by fibrous connective tissue and fat, leading to pseudohypertrophy of the affected muscles. Inflammatory Response: There is an increased presence of inflammatory cells, including macrophages and lymphocytes, around the necrotic and regenerating fibers. Variation in Muscle Fiber Size: Affected muscles display a wide variation in fiber size, with small regenerating fibers and large hypertrophic fibers. Internal Nuclei: An increased number of muscle fibers with internalized nuclei, which is a sign of ongoing muscle fiber regeneration and repair.
