Findings:

 Sonographic examination revealed a poorly defined intramuscular mass with an in homogeneous echo texture and multiple well-defined, anechoic, oval or tubular lesions in the subcutaneous tissue.

MRI revealed an ill-defined mass in the adductor longus muscle and multiple cysts with surrounding edema in the subcutaneous tissue.

Differential Diagnosis:

 Imaging findings were consistent with an inflammatory lesion rather than a neoplasm, although the intramuscular lesion was confused with a soft tissue neoplasm.

Diagnosis:  

 Surgical excision was performed. Pathologically, the mass showed tubular tracts in the subcutaneous tissue, possibly representing the pathway along which the larvae had passed. The walls of the tracts were composed of foreign body granulomatous reaction.

In the muscular component of the mass, a tapeworm segment was found and carefully extracted from the lesion. The worm was identified as a sparganum of Spirometra species.

Discussion:

 In an endemic area the differential diagnosis of an intramuscular mass accompanied by cystic, tubular tracts in the adjacent subcutaneous tissues should include musculoskeletal sparganosis.