Rhabdomyosarcoma of the head and neck in adults: MR and CT findings.

PURPOSE To evaluate imaging findings of rhabdomyosarcoma of the head and neck in adults. METHODS We examined 11 patients (seven men and four women; 17 to 73 years old) with pathologically proved rhabdomyosarcoma of the head and neck. The tumors originated in the paranasal sinuses (n = 6), cheek (n = 3), nasal cavity (n = 1), and infratemporal fossa (n = 1). Eight of the rhabdomyosarcomas were of the embryonal type, two were pleomorphic, and one was alveolar. Necrosis was seen in four patients, but calcification or intratumoral hemorrhage was not found. Two tumors had nodal extension. Contrast-enhanced CT was performed in 10 patients, and two patients had contrast-enhanced MR imaging. RESULTS On CT scans, the masses enhanced to the same degree as adjacent muscle. The masses showed a homogeneous pattern in six cases and a heterogeneous pattern in four cases. The tumor margins were poorly defined in eight cases. On MR images, the masses were homogeneously isointense with muscle on T1-weighted studies and were hyperintense relative to muscle on T2-weighted studies. On both CT and MR images, 10 of 11 cases showed poorly defined, homogeneous masses destroying adjacent bony structures. CONCLUSIONS MR imaging seems to be better than CT for initial and follow-up examination of patients with rhabdomyosarcoma because of its multiplanar capability and because it more precisely defines the extent of tumor.