INTRODUCTIONHydatid cyst of bone constitutes only 0.5-2% of all hydatidoses. The thoracic spine is the most common site of spinal hydatidoses. Primary hydatid cyst of the sacral spinal canal is rare.PRESENTATION OF CASEA 19-year-old man had cauda equina syndrome with pelvic pain 15 days ago, the pelvic radiography shows a lytic image depend on the left sacral wing. MRI showed an intra-pelvic cystic image invading the sacrum T1 hypointense and T2W hyperintense. The Hydatid serology was positive.Surgical treatment consisted of a wide drainage of hydatid cavity dug in the left sacral wing, and by which it communicated intra pelvic, with removal of the entire cyst by gentle aspiration, abundant rinsing with hypertonic saline, release and sacred roots encompassed in a puddle of fibrosis hydatid.The evolution was good with recovery of perineal sensation and anal tone. The sacroiliac joint was considered stable and did not require synthesis or reconstruction.DISCUSSIONHydatid cysts predominantly occur in liver and lungs. Involvement of other organs is uncommon. Neither surgery nor medical therapy is generally effective for bone, especially spinal hydatidosis. The initial treatment of choice is surgical excision for neural decompression and establishing diagnosis. Albendazole is the drug of choice against this disease, when suspected, presurgical use of Albendazole in Echinococcus infestations reduces risk of recurrence and/or facilitates surgery by reducing intracystic pressure.CONCLUSIONA missed diagnosis of hydatid cyst could be devastating. Hence, hydatid cyst should be kept as a differential diagnosis, when encountered with a cystic lesion of sacrum. In addition, longterm follow-up is mandatory as recurrence is high despite use scolicidal agents.

Objective:To compare diagnosis value of 1.5T and 3T MRI in the detection of traumatic knee injuries in young patients by reference to arthroscopy.Materials and Methods:One hundred patients were prospectively included. All patients randomly underwent standardized knee 1.5T or 3T MRI with subsequent knee arthroscopy. Meniscus and cruciate ligaments tears were blindly assessed by two independent musculoskeletal radiologists.Results:Comparison of 1.5T and 3T MRI groups in the diagnosis of medial and lateral meniscal tears showed significantly higher sensitivity (p = 0.015) of 1.5T MRI in the diagnosis of lateral meniscal tears. Sensitivity and specificity for complete ACL tears were 100 percent [35/35] and 100 percent [23/23] at 1.5T MRI (p = < 0.0001) versus 95.5 percent [21/22] and 100 percent [16/16] at 3T MRI (p = < 0.0001).Only three complete PCL tears were observed in this study. Sensitivity and specificity for all complete CL tears were 100 percent [37/37]; 100 percent [77/77] for 1.5T MRI (p < 0.0001); and 95.7 percent [22/23] and 100 percent [59/59] for 3-T MRI (p < 0.0001). Diagnosis value of 1.5T and 3T MRI was equal for ACL and PCL complete tears.Conclusion:Diagnosis value of 1.5T was similar to 3T MRI for medial meniscal and cruciate ligament tears of the knee in symptomatic patients and higher for lateral meniscal tears.

Authors describe the case of a patient with breast cancer and multiple myeloma as the second metachronous disease responsible for spinal cord compression. Synchronous occurrence of bone marrow breast cancer disease and multiple myeloma has not been described in the literature, as in this case. By presenting this case, we point to possible association between both diseases and the possible factors involved in the development of second malignant disease.

Melorheostosis is a rare entity belonging to the group of sclerotic bone dysplasias. Described for the first time in 1922 by Leri, it remains imperfectly known as clinical presentations are highly variable, and the etiological diagnosis is not fully elucidated. We report a case of polyostoticmelorheostosis for which radiological investigations were complete, in order to study this disease.

Giant-cell tumour (GCT) of the bone is a relatively uncommon tumour that is classified as benign. Pulmonary metastases appear in 3% of cases, usually over three years after the first diagnosis of the tumour. The authors reports a case of 28-years-old woman, treated for a giant-cell tumour with an early pulmonary metastases.