A rare intramuscular hydatid cyst of the gluteus: a case report

Hydatid disease is endemic to sheep-growing countries and typically involves the liver and lungs. Peripheral muscle involvement is atypical but should be considered in the differential diagnosis of soft tissue mass.

A 33-year-old male with right thigh pain and numbness found on magnetic resonance imaging (MRI) to have multiple cysts in the gluteus maximus, suspicious for myxoma. Biopsy revealed a parasitic organism and inflammation consistent with an extrahepatic hydatid cyst. Serologic studies showed a positive indirect hemagglutination test. Chest radiography and abdominopelvic imaging were negative for a cyst at other locations. The patient underwent en bloc pericystectomy followed by albendazole treatment for 3 months, after which the patient was asymptomatic and disease-free as evident on repeat MRI.

An intramuscular cyst is asymptomatic, and there is often a delay in diagnosis and treatment. When suspected on blood tests and imaging, clinicians must be cautious to avoid diagnostic puncture and accompanying complications of anaphylaxis and secondary cyst contamination and recurrence. A combination of surgical and nonsurgical options exists for the treatment of hydatid cysts, and the decision depends on cyst size and location.

Primary muscle hydatidosis is rare but responds well to a combination of surgery and anthelmintic medications. Complete and intact cyst removal is necessary to avoid complications and recurrence.