INTRACRANIAL EXTENSION IN NON-PARAMENINGEAL HEAD AND NECK RHABDOMYOSARCOMA. A REPORT FROM THE INTERGROUP RHABDOMYOSARCOMA STUDY (IRS)

Abstract

Intracranial extension of rhabdomyosarcoma (RMS) has been identified as a major cause of failure in parameningeal sites. Fifteen of 214 (7%) patients with nonparameningeal RMS had intracranial extension threatened or proven at diagnosis. The primary sites included: orbit (8), neck (2), cheek (2), parotid (1), oropharynx (1), and temporalis (1). Computerized tomographic scans in 13 cases were helpful in detecting the intracranial extension and defining the anatomical extent of the primary. One or more patterns of CNS extension were seen in the 15 patients: parameningeal extension (8), bony erosion of the orbit (7), infraorbital fissure involvement (4), brain metastases (3), meningeal metastases (2), cavernous sinus extension (2) and invasion of the optic nerve (1). Five of 6 cases receiving intrathecal chemotherapy and cranial radiotherapy according to guidelines for parameningeal sites survived. Metastases to the meninges and brain carried the gravest prognosis with no survivors. In the remaining patients 10/11 are alive at a median of 11 months from diagnosis. Careful evaluation of all patients with head and neck RMS may reveal threatened or proven intracranial extension. In these cases management according to guidelines for parameningeal head and neck sites is recommended.