Right thigh rhabdomyosarcoma




Clinical history: 44-year old man with progressively enlarging right thigh mass

Diagnosis: Rhabdomyosarcoma

Imaging techniques:

Imaging of the right thigh was performed on a 3T MR system (Skyra, Siemens). (A) Coronal T2-weighted TIRM (TR/TE 3000/38), (B) sagittal T2-weighted TIRM (TR/TE 3000/38ms), (C) axial T1-weighted TSE (TR/TE 700/12ms), and (D) T2-weighted TSE images with Dixon fat suppression (TR/TE 2600/91ms) were acquired along with contrast-enhanced T1-weighted TSE images with Dixon fat suppression (TR/TE 450-775/11) in three orthogonal planes (E, F, G).

Imaging findings:

Pre-contrast MR imaging demonstrates a heterogenous mass located inferiorly to the inguinal triangle (i.e. the space between the adductor muscles, vastus medialis and rectus femoris). The lesion exhibits predominantly isointense signal on T1WI and markedly heterogenous high signal on FS T2WI. A large cyst with fluid-fluid levels associated with the lesion can be seen on both T1 and T2WI, suggestive of intratumoral cysts and necrosis. Signal changes of peritumoral and anterolateral subcutaneous edema are seen on T2WI. After administration of contrast, the lesion exhibits marked, heterogenous enhancement.