Pan-limb Plexiform Neurofibroma-Hypothesis of Pathogenesis and Its Surgical Strategy

Abstract

Plexiform neurofibroma is a multi-nodular and diffuse benign peripheral nerve sheath tumor and is usually associated with neurofibromatosis type 1. Plexiform neurofibroma of the brachial plexus is rare. Plexiform neurofibroma of the whole upper limb, presenting with multiple nodular tumor masses from cervical nerve roots along the course of the brachial plexus and at the termination of the peripheral nerves is especially rare. Here we report two cases of pan-limb plexiform neurofibroma with similarity in symptoms and signs: diffuse nerve tumor masses, cutaneous pigmentation (cafe-au-lait spots) and severe neurological deficits of the upper limb. Case 1, a 28-years-old lady with Von Recklinghausen's disease presented with diffuse swelling and weakness of the left upper limb. Case 2, a 3-years- old boy, presented with multiple masses over the right neck with dropped shoulder and progressive inability to flex his elbow over the duration of one year. Both of them received cervical spine surgery for cord decompression and peripheral nerve surgeries for the limb tumor growth. They both had multiple nerve tumors resection and received palliative reconstruction: by tendon transfer and nerve transfer. Based on the clinical and intraoperative findings of these two cases, we made our hypothesis in tumor genesis and progression. ”Neighboring transmission” in such ”pan-limb” plexiform neurofibroma is proposed. Although it is rare, once it develops, it often results in severe neurological deficits and is a big challenge to the surgeon for both tumor resection and reconstruction. Early radical excision to prevent pathological neurogenic tumor spreading is probably one of the best choices of treatment. Late reconstruction by tendon, muscle, or nerve transfer, similar to the treatment of brachial plexus injuries is then supplemented.