UNASSIGNED: Hydatid disease can affect any human organ. The occurrence of hydatid cysts in psoas muscle is rare, accounting for only 1-3 % of cases, and even in endemic regions. However, the presence of multiple cysts is even more rare.
METHODS: A 40-year-old female from a rural area presented with abdominal pain. Physical examination revealed tenderness in the right hypochondrium. Her medical history pulmonary hydatid cystectomy seven years ago. Radiology investigation showed a two-hydatid cyst within the left psoas major muscle. Cystectomy of two hydatid cyst was performed. The patient was prescribed albendazole at a dose of 15 mg/kg, and at the latest month\'s follow-up appointment, the patient did not experience any relapse.
UNASSIGNED: This case presents a rare instance of multiple hydatid cysts in the psoas muscle, highlighting the importance of considering atypical presentations in endemic regions.
CONCLUSIONS: This case highlights the rarity of psoas major muscle hydatid cysts in a middle-aged woman from a rural area. Early recognition, accurate radiological assessment, and proper surgical treatment are crucial for positive outcomes and averting complications like infection, compression of nearby structures, or anaphylactic reactions.

Echinococcosis is a parasitic disease produced by the larval stage of Echinococcus granulosus. Hydatid disease of bone is rarely seen in humans and it has been reported in only 1-2% of cases of echinococcosis. We present a patient who developed hydatid disease of the left pelvic and femoral bones with cartilage destruction of the ipsilateral hip joint revealing a retroperitoneal location of hydatid cyst. Hydatid bone must be present in the differential diagnosis of chronic monoarthritis. Skeletal involvement is usually secondary to visceral hydatidosis that we must research. Early diagnosis allows eradication and salvage of the bone and the hip joint. Delayed diagnosis is always fraught with the risk of recurrence and sepsis.