[Osteonecrosis of the iliac in the differential diagnosis of malignant lesions of the hip].

A 46-year-old patient with an 8-month history of right lumbar sciatic pain non-responding to conservative treatment and progressive loss of proximal strength in the lower right extremity is presented. Simple radiography showed a right supraacetabular radiodense area. CT scan confirmed the presence of a mixed lesion with lithic areas and a dense aggregate which seemed to correspond to chondroidmatrix.MR imaging showed a lesion of tumoral appearance in the right acetabular region circumscribing the iliac bone with characteristics of aggressiveness based on permeation and cortical rupture leading to a diagnosis of chrondrosarcoma. A CT study showed no evidence of metastasis. A 3-phase bone scintigraphy centeredon thehips after the administrationof 99mTcMPD (925MBq) and a whole-body scan demonstrated a single