[Lumbo-pelvic stabilisation following subtotal sacrectomy due to a giant invasive schwannoma. Case report].

The case of a rare giant invasive schwannoma of the sacrum is presented. This is a slow-growing tumour reaching a large size because of non-specific symptoms. Even though it is benign in nature, it has characteristics markedly differing from commonly-known neurinomas; it invades and destroys bone, on MR examination it shows a heterogeneous structure reminiscent of a malignant process and its growth around the nerve roots makes nerve dissection in the cauda equina very complicated. At the time of diagnosis a major part of the sacral bone is usually destroyed and nerve root dissection is very difficult. In this case, because of removal of most of the tissue, an almost complete sacrectomy was necessary including the sacral roots with the exception of S1. At the second stage, lumbo-pelvic stabilisation was carried out using the modified Galveston technique. Since only a very few similar cases have been reported, it is not possible to predict the post-operative outcome in terms of potential recurrence or residual progression. In our patient a small residuum was stable even at 37 months after surgery. She remained incontinent after surgery, but able to walk unaided. Radiographic examination showed the osteosynthetic material without signs of loosening and in a good position.