Not to be confused withPseudoathletic appearance which can include pseudohypertrophy, but also hypertrophy among other pathological forms of enlargement
False enlargement of muscle due to infiltration of fat or other tissue
Medical condition
Pseudohypertrophy
Other names
false enlargement
Drawing of seven-year-old boy with Duchenne muscular dystrophy. There is pseudohypertrophy of the lower limbs.
Pseudohypertrophy, orfalse enlargement, is an increase in the size of an organ due toinfiltration of a tissue not normally found in that organ.[1] It is commonly applied to enlargement of a muscle due to infiltration of fat or connective tissue,[2] famously inDuchenne muscular dystrophy. This is in contrast with typicalmuscle hypertrophy, in which the muscle tissue itself increases in size.[2] Because pseudohypertrophy is not a result of increased muscle tissue, the muscles look bigger but are actually atrophied and thus weaker.[2][3] Pseudohypertrophy is typically the result of a disease, which can be a disease of muscle or a disease of the nerve supplying the muscle.[2]
In pseudohypertrophy where the atrophied muscle tissue has been infiltrated by fat tissue, upon palpitation the seemingly large muscles feel doughy.[3]
Not all muscles infiltrated by fat or other tissue are pseudohypertrophic. In muscularsteatosis, sometimes the muscles may appear a normal or a slender size, even though the atrophied muscle has been infiltrated with fat tissue, such as the calf muscles inBethlem myopathy 1.[4][5][6][7][8] Inmyosclerosis, the muscle is infiltrated with connective tissue and fibrosis, having a firm, "woody" feel upon palpitation, with the muscles appearing slender.[9][10]
As well as being known as 'false enlargement,' when the muscle has been infiltrated by fat tissue, historically it has also been called muscularsteatosis, pseudohypertrophic atrophy,lipomatous pseudohypertrophy, interstitiallipomatosis, lipomatous muscular dystrophy, or atrophia lipomatosa.[12] It is also known asfatty atrophy of muscle (not to be confused with fat atrophy, which is atrophy of adipose tissue), as muscle tissue is replaced by fat tissue, the actual muscle atrophies while the fat tissue replaces the bulk.[13]
^Suh, B.C.; Choi, Y.C.; Kim, S.M.; Choi, B.O.; Shim, D.; Lee, D.H.; Sunwoo, I. (2006). "A Family of Bethlem Myopathy".Journal of the Korean Neurological Association.24:614–617.S2CID74251729.
^Merlini, L.; Martoni, E.; Grumati, P.; Sabatelli, P.; Squarzoni, S.; Urciuolo, A.; Ferlini, A.; Gualandi, F.; Bonaldo, P. (2008-10-14). "Autosomal recessive myosclerosis myopathy is a collagen VI disorder".Neurology.71 (16):1245–1253.doi:10.1212/01.wnl.0000327611.01687.5e.ISSN1526-632X.PMID18852439.
^Cros, D; Harnden, P; Pellissier, JF; Serratrice, G (January 1989). "Muscle hypertrophy in Duchenne muscular dystrophy. A pathological and morphometric study".Journal of Neurology.236 (1):43–7.doi:10.1007/BF00314217.PMID2915226.S2CID23619631.
