Macrodystrophia lipomatosa: radiographic diagnosis.

Macrodystrophia lipomatosa is a rare form of localized gigantism characterized by progressive overgrowth of all the mesenchymal elements with a disaproportionate increase in the fibroadipose tissues. This congenital abnormality occurs most frequently in the distribution of the median nerve in the upper extremity and in the distribution of the planter nerves in the lower extremity. It is usually recognized at birth or in the neonatal period. As the patient grows, the deformity begins to mechanically interfere with joint function, vascular supply, and innervation. Six cases are described with emphasis on the radiographic findings which differentiate this entity from other forms of local gigantism. These findings include a predominately distal involvement, enlargement of the phalanges and soft tissue elements of the digit, and lucencies within the soft tissues.