RESUMEN
Hydatid disease is caused by the tapeworm of genus ;Echinococcus. Genus Echinococcus has different species including Echinococcus vogeli, Echinococcus granulosus and Echinococcus multilucularis. Echinococcus granulosus is the most common cause of hydatid disease in humans. This disease can take place either directly through ingestion of parasite eggs from contact with infected dogs or indirectly from the ingestion of contaminated water or food. Infestation of hydatid disease in humans most commonly occurs in the liver (55-70%), followed by the lungs (18-35%). Bone hydatidosis however is very rare,whenever it occurs; it is usually secondary to visceral involvement. We present herein a case of primary hydatid cyst involving superior pubic ramus in a 43 years male patient, which is not a common site for the occurrence of this disease. Diagnosis is usually delayed if high index of suspicion is not there. MRI is a good tool for reaching diagnoses.