[MRI and CT diagnosis of rhabdomyosarcoma in the extremities:a report of nine cases].

BACKGROUND & OBJECTIVE: Imaging studies on rhabdomyosarcoma in the extremities have seldom been reported. This study was to explore the MRI and CT features of rhabdomyosarcoma in the extremities.

METHODS

MRI and CT data of 9 patients with rhabdomyosarcoma in the extremities were analyzed.

RESULTS

Among the 8 cases that received MRI examination, as compared with muscle, all tumors showed mixed low and intermediate signal intensity on T1WI, with the later being predominant; all tumors showed intermingling areas of hyper-, iso-, and/or hypo-signal intensity on T2WI; after Gd-DTPA injection, all tumors showed strong and heterogeneous enhancement. Five of them showed ill-defined margin and surrounding edema, the other 3 were well-circumscribed without conspicuous edema. Of the 3 cases that received CT examination, all tumors showed both low and intermediate density as compared with muscle on un-enhanced images, with the later being predominant; none of them showed calcification; 2 of them were ill-defined and the other 1 was well-circumscribed. The case that received contrast-enhanced CT examination showed strong and heterogeneous enhancement. Among all 9 cases, 8 showed necrosis or cystic changes, none showed hemorrhage and invasion of adjacent bone, but 3 showed adjacent blood vessel encasement and 1 showed tumor thrombosis in the adjacent vein.

CONCLUSION

When MRI or CT reveals a soft tissue mass in the extremity with necrosis and strong and heterogeneous enhancement, especially when hemorrhage, calcification and adjacent bone invasion is not present,rhabdomyosarcoma should be considered.