[An unusual cause of sciatica: soft tissue desmoid tumor. Apropos of 2 cases].

The authors report 2 cases of sciatica resulting from nervous compression by a desmoid tumour in women aged 33 and 27 years. In each case, careful exeresis did not prevent recurrence as shown by tomodensitometry. Eight other well-documented cases were found in the literature. The desmoid tumour penetrates the buttock and thigh muscles and presses the sciatic nerve. The patients often suffer from previous and persistent sciatica which can combine with hip restriction. The responsible tumour made up of abundant bundles of collagenous fibers, a small number of fusiform cells without mitosis or atypics and on the periphery degenerative and dissociated muscle fibers is usually discovered late. Tomodensitometry is the best means of detection, evaluation of the extent, adhesions and recurrence during the observation period. Treatment is usually surgical and success depends on the quality of the exeresis. Other methods, corticoid, anti-oestrogen and radiotherapy, sometimes effective in desmoid tumours of the abdominal wall, do not prevent recurrence in the buttocks or thighs which are of sciatic derivation.