Intracranial extension of rhabdomyosarcoma from the face, nasopharynx or middle ear is rare. A 16-year-old boy presented with deterioration of vision and headache. CT scan revealed a soft tissue mass occupying the sphenoid and ethmoid sinuses, extending to the suprasellar fossa and impinging on the optic chiasm. The tumour, mimicking pituitary carcinoma, was removed by transsphenoidal craniotomy. Morphologic studies, including immunohistochemistry and electron microscopy, revealed that the tumour was a rhabdomyosarcoma. This case stresses the value of immunohistochemical and ultrastructural studies in the diagnosis of tumours occurring in the region of the sella turcica. The origin of this tumour was thought to be the sphenoid or ethmoid sinus. The pituitary gland appeared intact.