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Ganglion cysts arising from the temporomandibular joint are rare entities that often present with swelling and minimal to no pain in the preauricular region. To the authors' knowledge, a temporomandibular joint ganglion cyst occurring with acute facial nerve palsy and intracranial extension has never been reported. The patient in the current case initially underwent treatment for Bell palsy and then draining of the cyst at an outside hospital with no relief of symptoms. Repeat MR imaging showed an increase in the size of the cystic, enhancing, middle fossa lesion measuring 4 cm. Resection of the lesion was undertaken using a middle fossa approach. After a satisfactory surgical decompression, the patient demonstrated a significant recovery in her facial palsy over a 3-month period of time. This case presents new clinical and radiographic findings associated with these lesions.

Background and Purpose: The imaging appearance of facial nerve schwannomas (FNSs) has been described as an enhancing tubular mass (using T1-enhanced MR) within an enlarged facial nerve canal (using CT). The purpose of this study is to identify how often the FNS imaging findings conform to this description and determine whether there are underlying anatomic explanations for the discrepant imaging appearances identified., Materials and Methods: The clinical, pathologic, and radiologic records of 24 FNS in 23 patients were retrospectively reviewed. Each FNS was evaluated for location along the facial nerve. The lesions were cataloged by facial nerve segment with the imaging characteristics of each segment described., Results: The average age at time of first imaging was 39 years (age range, 10-70 years). Eighteen (71%) of the 24 FNSs were pathologically confirmed, while the others were determined intraoperatively or diagnostically by the presence of both enlargement of the facial nerve canal and enhancement on contrast-enhanced T1 MR examination. The most common location was in the geniculate fossa (83%), followed by the labyrinthine and tympanic segments of the facial nerve (both 54%). The most common clinical presentation was facial neuropathy (42%)., Conclusion: The classic description of FNS on enhanced T1 MR is that of a well-circumscribed fusiform enhancing mass along the course of the intratemporal facial nerve with bone algorithm CT showing sharply defined bony canal enlargement. Modern imaging techniques, however, demonstrate the importance of the surrounding anatomic landscape, leading to various imaging appearances. Lesions traversing the labyrinthine segment can demonstrate a dumbbell appearance. When FNSs track along the greater superficial petrosal nerve, they may present as a round mass projecting up into the middle cranial fossa. FNS of the tympanic segment of the facial nerve preferentially pedunculate into the middle ear cavity, clinically presenting as a middle ear mass. When the mastoid segment of the facial nerve is involved, irregular and "invasive" tumor margins seen on MR can be explained on CT as tumor breaking into surrounding mastoid air cells.

Anomalies of the course of the facial nerve have been reported in association with middle and inner ear malformations. Bifurcation of its intratemporal portion is a rare malformation in which focal splitting of one or more facial nerve segments occurs. We describe the CT appearance of this anomaly and discuss its possible embryology. Facial nerve bifurcation is important to recognize in patients undergoing evaluation for congenital hearing loss and other congenital ear malformations.

Background and Purpose: Benign tumors of the internal auditory canal (IAC) may leave the confines of the IAC fundus and extend into inner ear structures, forming a dumbbell-shaped lesion. It is important to differentiate dumbbell lesions, which include facial and vestibulocochlear schwannomas, from simple intracanalicular schwannomas, as surgical techniques and prognostic implications are affected. In this article, the imaging and clinical features of these dumbbell schwannomas are described., Methods: A dumbbell lesion of the IAC is defined as a mass with two bulbous segments, one in the IAC fundus and the other in the membranous labyrinth of the inner ear or the geniculate ganglion of the facial nerve canal, spanned by an isthmus. Twenty-four patients with dumbbell lesions of the IAC had their clinical and imaging data retrospectively reviewed. Images were evaluated for contour of the mass and extension into the membranous labyrinth or geniculate ganglion., Results: Ten of 24 lesions were facial nerve dumbbell lesions. Characteristic features included an enhancing "tail" along the labyrinthine segment of the facial nerve and enlargement of the facial nerve canal. Dumbbell schwannomas of the vestibulocochlear nerve (14/24) included transmodiolar (8/14), which extended into the cochlea, transmacular (2/14), which extended into the vestibule, and combined transmodiolar/transmacular (4/14) types., Conclusion: Simple intracanalicular schwannomas can be differentiated from transmodiolar, transmacular, and facial nerve schwannomas with postcontrast and high-resolution fast spin-echo T2-weighted MR imaging. Temporal bone CT is reserved for presurgical planning in the dumbbell facial nerve schwannoma group.

The clinical, radiographic, and pathologic records of 39 patients with peripheral facial nerve dysfunction seen from October 1981 through July 1984 are reviewed. The extent of preradiologic clinical localization of suspected lesions and their subsequent pathologic confirmation is correlated to the number, sequence, and type of radiographic evaluations performed.

Peripheral facial nerve dysfunction may have a clinically apparent or occult cause. We reviewed the clinical and radiographic records of 36 patients with peripheral facial nerve dysfunction to obtain information on the location of the suspected lesion and the number, sequence, and type of radiographic evaluations performed. Inadequate clinical evaluations before computed tomography (CT) was done and unnecessary CT examinations were also noted. In those patients in whom the cause of peripheral facial nerve dysfunction is apparent, the clinical-radiographic workup is self-evident. When the cause of dysfunction is occult, however, a tailored CT examination should be done based on a thorough clinical evaluation. We have suggested a practical clinical and radiographic scheme to evaluate progressive peripheral facial dysfunction with no apparent cause. If this scheme is applied, unnecessary radiologic tests and delays in diagnosis and treatment may be avoided.