Musculoskeletal hydatid infections are a very rare form of hydatid disease.
For a general discussion, and for links to other system specific manifestations, please refer to the article on hydatid disease.
Patients usually present with slow growing swelling with or without pain.
They can present almost anywhere, but most common locations are:
- vertebrae (see spinal hydatid disease) and para-vertebral soft tissue
- femur and soft tissue of lower limb
- may show expansile lytic lesion in the involved bone which can be unilocular or multilocular with coarse trabeculae
- thinning of cortex
- adjacent soft tissue swelling may be seen due to direct extension from the bone or co-existing multiple soft tissue lesions
Ultrasound may depict lesions in the soft tissue which can be solitary/multiple unilocular/multilocular/complex cystic lesions and/or atypical solid hypoechoic lesion.
Better delineates expansile unilocular or multilocular lytic lesion and demonstrates any soft tissue extension. Co-existing soft tissue multilocular cysts may be seen.
T1: hypointense cyst
- may show low-intensity rim
- T1 C+: shows wall enhancement
T2: hyperintense cyst (uni/multilocular) with a low-intensity rim
- water lilly sign may be seen