Lipofibroma of the median nerve in the palm and digits of the hand.

Lipofibroma of the median nerve or its cutaneous branches is a rare benign tumor. The diagnosis is usually made at surgical exploration of a mass in the distal part of the forearm, the wrist, the palm, or the digits of the hand, which may be asymptomatic or associated with symptoms of carpal-tunnel syndrome. The diagnosis should be made when exploration reveals fusiform enlargement of a segment of the median nerve or its cutaneous branches without hypertrophy of the regional tissues. The tumor is limited to within the epineurial sheath, which is intact, shiny, orange-yellow, firm, thick, and non-resilient to dissection. The nerve tumor does not infiltrate the surrounding tissues nor do the surrounding tissues infiltrate the nerve. If the epineurium is opened, the nerve fibers are found to be inseparably infiltrated by fibrous and fatty tissues. Histologically, these are of epineurial, perineurial, and endoneurial origin. A forzen-section biopsy of a palmar cutaneous branch is suggested to confirm the diagnosis. Once the diagnosis is confirmed, the treatment should be limited to release of the fascia over the involved nerve. The tumorous part of the median nerve was partly or completely excised in seven of twenty-six cases reviewed in the literature and this report. It is to emphasize a conservative approach when such a tumor of the median nerve is encountered at surgery that we describe two more cases.