INTRODUCTION :
Hydatid cysts are a common parasite in endemic countries, frequently found in the liver and lungs. Although bone echinococcosis is rare, with a frequency of only 1-2%, Diagnosis is often delayed due to the lack of specificity and clinical latency that characterise this disease. It is based on a combination of clinical, biological and radiological factors, and only pathological examination can confirm the disease. Imaging is used to confirm the diagnosis, assess lesions and monitor disease progression. This report presents an exceptional case of a hydatid cyst of the sacrum, illustrating its clinical and radiological features, as well as the therapeutic difficulties associated with this condition.