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March 1950

STUDIES IN DISORDERS OF MUSCLE: III. "Pseudohypertrophy" of Muscle in Progressive Muscular Dystrophy and Other Neuromuscular Diseases

Arch NeurPsych. 1950;63(3):425-432. doi:10.1001/archneurpsyc.1950.02310210071005

ENLARGEMENT of muscles in progressive muscular dystrophy was noted in the earliest descriptions of the disease.1 In fact, it has been such a striking finding in many of the cases that a classification has been based on this sign ("pseudohypertrophic" and "atrophic" types).

The enlarged muscles feel doughy on palpation and are weaker than normal. The term "pseudohypertrophy" distinguishes this form of enlargement from real hypertrophy. The latter occurs after intensive use of muscles, as, for example, in weight lifters, and in certain diseases characterized by spasticity of muscles. Grossly, the "pseudohypertrophic" muscles in the muscular dystrophy of childhood show loss of pigment and a "fish flesh" appearance. Microscopically, one finds atrophic fibers and large fibers which stain abnormally and show loss of striation. Intermixed with the normal and abnormal muscle fibers is a great excess of fat and fibrous tissue.

Clinical descriptions of so-called pseudohypertrophic progressive muscular dystrophy