[The fibrolipomatous hypertrophy of the main nerves of the upper extremity].

10 cases of lipofibromatous hypertrophy of the main nerves in the upper limb in 7 female and 3 male patients are described. In 1 case at the level of the middle third of the upper arm and in 6 cases at the level of the wrist and neighboring areas. In 2 patients these pathological changes were found in the ulnar nerve, in 1 case the hypertrophy was limited to the upper arm, in the other it extended all along the extremity from below the axilla to the wrist. Finally, in 1 case a 20 cm long hypertrophy was found at the level of the deep branch of the radial nerve (posterior interosseus nerve) in the lower arm below the elbow. The fibrous and lipomatous tissue snugly surrounds the fascicles and cannot be separated from them without damaging them, even if the finest microsurgical techniques are used. As the disease has been diagnosed in children as young as five years a congenital etiology has to be considered. The condition is distinct though from the disease of DEJERINE-SOTTAS or from that of von RECKLINGHAUSEN. The hypertrophic nerve is progressively submitted to a chronic compression in the naturally narrow passages (carpal tunnel, ulnar grove at the elbow, arcade of FROHSE) or it becomes painful and paretic after even minor trauma which leads probably to local oedema, intraneural bleeding and epineural compression. An external and internal decompression has to be carried out. Resection or defatting of the hypertrophic fascicles, however, should be avoided. In 2 of our cases the disease was anamnestically present for 45-50 years and clinically followed in another case for 18 years. The disease does not seem progressive. These cases show, that this disorder, which first appeared in the medical literature in 1964 and have been described by several authors in the median nerve, exists as well in the two other main nerves of the upper extremity.