[Pseudo-sciatica of neoplastic origin: apropos of an unusual case].

The authors report a case of 'pseudosciatic' pain due to bone metastasis located in the sacroiliac joint secondary to breast cancer. Complementary investigations are mandatory in any case of sciatic pain starting at 80 years of age, even in the absence of the usual criteria suggesting a neoplastic origin. In this case our investigations revealed sacroiliac bone metastasis from the breast, explaining the clinical picture. Primary and secondary sacral tumors are uncommon. Their clinical manifestations are unspecific, consisting mainly of low back pain and sciatic pain. CT scan and MRI are the best tools to evaluate these lesions. Conservative management, combining radiotherapy and hormonal treatment, has been effective in terms of both pain and function.