Background: Hydatid disease is a parasitic infection that is endemic in Iran. It infests humans and herbivorous animals and reflects infection by Echinococcus granulosus. Although it can develop anywhere in the body, the liver and lungs are the most common sites of involvement. Primary muscular hydatidosis with no involvement of thoracoabdominal organs is a rare event.
Methods: Case report and review of relevant literature.
Results: We treated a 27-year old male patient with a swelling on his right shoulder that turned out to be a hydatid cyst by magnetic resonance imaging scan. The treatment included surgical excision combined with post-operative anthelminthic administration. Of the total reported cases of hydatidosis, 0.7-3% were described as musculoskeletal cysts.
Conclusions: Especially in endemic areas, to avoid fine-needle biopsy and the risk of spillage of cyst contents irrespective of their location, hydatid disease should be considered in the differential diagnosis of muscular masses, and the diagnosis should be made by imaging and serology insofar as possible.