Macrodystrophia lipomatosa

Last revised by Joshua Yap on 7 May 2023

Macrodystrophia lipomatosa is a rare form of localized gigantism, and many terms have been used interchangeably, with resulting confusion. They include macrodactyly, megalodactyly, digital gigantism, macromelia, partial acromegaly, macrosomia, and limited gigantism 3.

Macrodystrophia lipomatosa can be thought of as lipomatosis of nerve resulting in visible deformity. It is also worth noting that macrodystrophia lipomatosa is essentially analogous to static localized gigantism (as described by Barsky in 1967) 3

Macrodystrophia lipomatosa is a congenital but non-hereditary condition, and is usually identified in the neonatal period 3

Recognized associations include:

This condition typically presents with painless enlargement of the 2nd or 3rd digit of the hand or foot. It is usually unilateral but may involve adjacent digits in the distribution of the median or plantar nerves. Occasionally it involves the entire limb 3

Macrodystrophia lipomatosa is characterized by a marked increase in all mesenchymal elements 1. This is dominated by adipose tissue in a fine fibrous network involving periosteum, bone marrow, nerve sheath, muscle, and subcutaneous tissue.

Plain films usually suffice and demonstrate splayed, lengthened and broadened phalanges with endosteal and periosteal bone deposition.

The overlying soft tissues are markedly overgrown, especially in the volar and distal aspects. Within the soft tissues, focal lucent areas representing fat may be seen, which is characteristic.

MRI is helpful in distinguishing macrodystrophia lipomatosa from other causes of macrodactyly (see below). It demonstrates accumulation of fat in the subcutaneous tissues without a discernable capsule 1. There might be fibrous strands seen within this accumulated fat with cortical thickening, osseous hypertrophy, and bony outgrowths from the underlying bone. Neural thickening may also be visualized.

Although macrodystrophia lipomatosa is considered a progressive form of macrodactyly (i.e. the growth of the affected parts is faster than the rest of the body) growth halts at puberty 4.

As such treatment is reserved for cosmesis and when the mechanical function is impaired. 

The term was first coined in 1925 by Hans Feriz (1895-1970), a German physician 6.

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