Imaging of rhabdomyosarcomas of the head and neck.

Rhabdomyosarcoma (RMS) is the most common childhood malignancy of the head and neck. The Intergroup Rhabdomyosarcoma Study now divides head and neck RMS into three categories by site of origin: orbital, parameningeal (middle ear, paranasal sinuses, and nasopharynx), and all other head and neck sites. CT is clinically applicable in the diagnosis of RMS of the head and neck, in treatment planning, and in the follow-up of patients with these tumors. Specific areas of applicability include determination of the presence/absence of intracranial and meningeal involvement, definition of tumor extent to guide radiation therapy planning, and demonstration of tumor regression or recurrence during and after treatment. CT has played an important role in the dramatically improved prognosis seen in RMS over the last 10 years. The role of MR in evaluating these patients is not yet defined, but it has promise because of the ease of obtaining multiple projections and the avoidance of ionizing radiation.