gms | German Medical Science

Objective: Plexiforme neurofibromas (PNF) in NF1 and – less often – plexiforme schwannomas in NF 2 are a significant source of suffering in NF patients. If present at a young age they grow significantly in the first 2 decades of life during the natural growth period. They are mostly symptomatic with pain. Due to their plexiforme nature and the involvement of the whole nerve, several major nerves or the whole limb, they are often regarded as inoperable. Apart from pain, the cosmetic disfigurement and the risk of malignancy in growing NF1-associated PNF are an indication for surgery. We report our experience in the surgical treatment of PNF in children.

Methods: In 15 children 18 PNF (intraspinal nerve roots, brachial plexus, median nerve, ulnar nerve, femoral nerve, obturator nerve, ischiadic nerve, peroneal nerve) were microsurgically removed. Indication for surgery was pain and growth in 13 children, two had asymptomatic, but fast growing abdominal tumors. Surgery was performed under neurophysiological monitoring of motor function.

Results: A significant tumor mass reduction could be achieved all 13 children with extra-abdominal tumors operated because of disfigurement, pain and growth. None of the children suffered a peri-operative loss of motor function. There was some loss of sensation in a few children which partially recovered at follow-up. There was no problem with wound healing. No significant tumor recurrence and no return of pre-operative symptoms during the follow-up of maximum 2.5 years was found. The two children with abdominal tumors were found to harbor an MPNST. Here loss of motor function was calculated as part of radical removal. Both suffered rather fast recurrences, one died, the other is in a palliative state with multiple distant metastases.

Conclusions: Despite the plexiforme nature PNF are a good target for surgical therapy in symptomatic cases. With an appropriate microsurgical technique under high magnification and with neurophysiological monitoring resection is safe in experienced hands and the benefit for children is remarkable. We advocate early surgical treatment of PNF as soon as the tumors present, since a) follow-up studies have shown that PNF always grow during childhood and adolescence, b) growth leads to pain and disfigurement c) the risk of malignant transformation in the further course of growth exists and d) resection is more easy and with less associated risks the smaller tumors are.