Bone and Intramuscular Hydatid Cysts: A Rare Association

Abstract

<i>Background:</i> Hydatidosis is a parasitic disease linked to the development of Echinococcus Granulosus larval form in humans. This anthropozoonosis is characterized by many topographical and evolutionary aspects. Musculoskeletal hydatidosis is rare, it represents only 0.9 to 2.5% of all locations. <i>Objective:</i> the aim of this manuscript is to report a rare case of bone and muscle location of hydatid cyst and show the imaging contribution in its positive diagnosis and pre-therapeutic assessment. <i>Method:</i> We report the observation of a 61-year-old man admitted to our training for a right thigh mass, revealing a muscular hydatid cyst with a concomitant iliac bone location. <i>Result:</i> Ultrasound examination shows an intra muscular cystic lesion, of the Sartorius and rectus femoris muscles, with hydatid membranes inside. A simultaneous bone location, at the ipsilateral iliac bone, was fortuitously discovered on CT scan and MRI exploration, which show a multicystic lytic lesion with cystic signal and round daughter cysts on MRI examination. A complementary X-ray of the pelvis shows the classic "honeycomb" appearance of the right iliac bone. A positive hydatid serology confirmed the diagnosis. No concomitant hepatic or pulmonary localization was demonstrated on abdominal ultrasound and chest CT scan. An anthelminthic therapy (Albendazole) was started, and the patient was a candidate for further surgical treatment. <i>Conclusion:</i> Musculoskeletal hydatid cyst location is rare. The Hydatid osteopathy is usually infiltrative, slow and progressive, which makes diagnosis late and compromises the quality of treatment. So, despite its rarity; musculoskeletal hydatid cyst should always be considered in the differential diagnosis of cystic lesions in endemic areas.