Invasion patterns of advanced temporal bone malignancies

Primary malignancies of the temporal bone may originate in the external auditory canal, the middle ear, the endolymphatic sac, or the eustachian tube. The surgical treatment of advanced tumors in these regions is strictly dependent upon the radiographic delineation of disease extent and the tumor relationship to adjacent neurovascular structures. Twenty-six cases of stage III or IV squamous cell carcinoma of the temporal bone were retrospectively reviewed to correlate preoperative clinicoradiographic analysis with intraoperative findings. The following patterns of tumor invasion were identified: (a) superior erosion through the tegmen tympani into the middle cranial fossa; (b) anterior extension into the glenoid fossa and infratemporal space; (c) inferior growth through the hypotympanum and jugular foramen; (d) posterior involvement of the mastoid air cells; and (e) medial involvement of the middle ear and carotid canal. While otic capsule erosion was uncommon, several of these patients did present with lower cranial nerve palsies. Complex surgical procedures exist for the en bloc resection of advanced temporal bone cancers. Appropriate operative planning must be based upon a knowledge of potential patterns of tumor extension and meticulous radiographic assessment.