Zur Klinik und Pathologie der Makrodaktylie

Summary

Macrodactylism should be differentiated from the gigantism of fingers and toes observed in systemic diseases—as of the vessels (Klippel-Trenaunay disease), of the nerves (Recklinghausen's disease) and of the endocrine glands (Curtius' syndrome). Macrodactylism, having certain anatomical findings, is also to be distinguished from the so-called “big finger” or “big toe”, which is the pure hypertrophic form—all other tissues being normal.

The delayed healing, the poor blood circulation, the hypoaesthesia, and the progressive hypertrophy of the soft tissue are well known facts; the results of reduction plastics are very poor, because of the various complications.

For these reasons we tried to investigate this congenital malformation using light and electron microscopy.

Seven cases with macrodactylism of the toes were observed and treated. Surgery was performed between the ages of 8 months and three years. The affected toes were amputated or reduced, and the whole of the hypertrophic fat tissue of the metatarsal area was resected. In 5 cases the digital nerves were hypertrophic, and divided at the level of the metatarsal capitulum.

These cases, being in the area of the L₅-dermatome, were classified according to their localisation into three groups (Fig. 1).

Histologically, a hyperplasia of all types of tissue has been observed. The nerval and vascular abnormalities were the most remarkable findings, beside the parakeratosis and abnormal thickness of the skin.

The peri- and endoneural connective tissue was increased, however, without the degenerative changes of the nerves stated by Moore (1942). In electron microscopy the nerves have a similar construction to the normal peripheral ones described by Pease and Pallie. The Schwann cells, the fibroblasts and collagen fibres are increased. The axoplasm, nerve fibres and myelin sheaths were degenerated, and vacuoles and ruptures or irregularities of the myelin sheaths were observed. We interpret these findings as a consequence of the increased peri- and endoneural connective tissue. These degenerations could be also the cause of the hypoaesthesia observed in 4 of our cases.

Also, in the vascular system pathological changes have been found, such as an increased amount of endarteries and hyperplasia of the glomera. These changes could be the cause of the low blood-flow of the diseased extremity, as determined plethysmographically by Tuli, and also the cause of postoperative inflammation of the wound and of hypertrophic scars. In one case we were obliged to amputate the leg because of recurrent inflammation of bone and acro-osteolysis, which occurred one year later.

In conclusion, and according to our histological findings, we consider macrodactylism as a special form of neurofibromatosis, with a circumscribed dysplasia of all kinds of tissue. The cause of the hyperplasia could be a disturbance of the regulation of the nervous system, which is well known in other regions of the human body.

The pathogenic considerations and the histological findings, which explain the delayed healing and the poor operative results, justify the method proposed by Barsky for the treatment of macrodactylism:—amputation of the affected finger or toe, and resection of the hyperplastic fat tissue—combined, however, with excision of the digital nerves as recommended by Tsuge.

Zusammenfassung

Auf Grund von 7 licht- bzw. elektronenoptisch untersuchten Makrodaktyliefällen wird diese seltene Mißbildung als eine Sonderform der Neurofibromatose aufgefaßt. Als Ursache der Hyperplasie wird eine Regulationsstörung des Nervensystems angenommen. Die Amputation des befallenen Strahles mit hoher Durchtrennung der Digitalnerven wird als Therapie empfohlen.