Congenital macrodactyly: a clinical study.

Congenital macrodactyly is a rare congenital malformation characterised by progressive enlargement of all mesenchymal elements of a digit. The present study is an attempt to draw the attention towards the similarities and differences between macrodactyly of the hand and foot. Radiographical, operative findings and histopathological examination of five cases are included in the present study. Emphasis was given to know the possible basic lesion. Radiographic findings, which differentiate this entity from other forms of local gigantism, were also analysed. The most characteristic finding noted was excessive overgrowth of fibro-fatty tissue with unusually large fatty lobules, apparently fixed by a mesh of dense fibrous tissue. Hypertrophy and tortuosity of the digital nerve, a striking feature in macrodactyly of the hand, was notably absent in cases affecting the foot. None of the patients had any other associated congenital anomalies. Neither the patients nor any of their family members had any stigmata of neurofibromatosis. Chromosomal study was normal in all of them. We conclude that in macrodactyly of the foot, excessive proliferation and accumulation of adipose tissue was the basic lesion, whereas involvement of the nerve might be the fundamental lesion in gigantism of the hand. Furthermore, whatever be the basic lesion, the final pathway must be either the local deficiency of a growth inhibiting factor or local expression of a basic intrinsic factor, leading to excessive growth of all elements of the digit.