Facial nerve neuromas: MR imaging. Report of four cases

Facial nerve neuroma in the geniculate ganglion extending into the internal auditory canal: A case report

Facial nerve schwannoma is a very rare benign tumor representing less than 1% of intrapetrous lesions. Our patient is a forty-one year old female who has suffered from recurrent right facial palsy for the last six years. She was first misdiagnosed as having Bell's palsy and received corticosteroids which resulted in little improvement. She then had facial nerve decompression surgery which resulted in a partial improvement. Since then, she has suffered from recurrent attacks of facial palsy. Two years ago, she came to our hospital seeking further treatment options. The final diagnosis made by MRI was a possible facial nerve tumor. To obtain a better facial outcome, total tumor removal was performed through the middle cranial fossa approach along with facial-hypoglossal nerve end-to-side anastomosis through transmastoid approach. Her hearing was preserved, and she obtained a better facial outcome than that of her preoperative level. In conclusion, facial nerve schwannoma has the potential to be misdiagnosed as Bell's palsy which might lead to a delay in diagnosis, and end-to-side neurorrhaphy may be an effective alternative in a selected case.

Intraparotid facial nerve schwannoma: A case report

Facial nerve schwannoma occurring within the parotid gland is a rare tumour. We report a case of schwannoma within the parotid gland in a young female patient, who underwent ultrasound and magnetic resonance imaging (MRI) and subsequent surgical excision of the lesion. The lesion showed hyperintensity on T2-weighted and diffusion-weighted MRI. There was no adjacent lymphadenopathy. Although hyperintensity on diffusion-weighted MRI could suggest malignant tumours, the characteristic “string sign” provided the clue for the diagnosis of schwannoma.

Intraparotid schwannoma

Diagnoses most commonly associated with a unilateral parotid mass include sialadenitis, pleomorphic adenoma, Warthin tumor, and mucoepidermoid carcinoma. However, rare entities, such as intraparotid schwannoma, must be considered in the differential diagnosis. We present a brief literature review that is illustrative of the current difficulty of preoperative diagnosis of intraparotid schwannoma, which is an exceptionally rare entity, with approximately 80 cases described to date. It may mimic common neoplasms and inflammatory salivary gland conditions on fine-needle aspiration and imaging, but is more likely to be associated with the facial nerve. Depending upon the tumor's spatial relationship to the facial nerve and the extent of neurologic dysfunction, the decision may be made to observe the tumor rather than attempt resection. This potential implication for patient management is a critical consideration that highlights the need for timely, appropriate biopsy and diagnosis.

Neurofibroma of facial nerve presenting as parotid mass

Neurogenic neoplasms presenting as parotid gland tumors are extremely uncommon. We present the case of a solitary neurofibroma of the facial nerve within the parotid gland occurring in a 36-year-old male who presented with a painless enlargement in the right-side region of the parotid gland over a period of 1 year with normal facial nerve function. Magnetic resonance imaging revealed a well-demarcated round mass within the right parotid. At surgery, a tumor was found involving the main trunk of the facial nerve, histopathologically representing a neurofibroma.

Intraparotid Facial Nerve Schwannoma

Intraparotid facial nerve schwannoma is a rare benign neoplasm. Due to its rarity, it is not usually a prioritized diagnosis before surgery and may therefore lead to an unintentional treatment error. In this article, we report a single case of intraparotid facial nerve schwannoma. We were able to make a diagnosis with frozen biopsy. A complete resection of the mass while preserving the facial nerve was performed. Herein we present our clinical experience with regards to the treatment process of intraparotid facial nerve schwannoma.

Enlarged geniculate ganglion fossa: CT sign of facial nerve canal fracture

RATIONALE AND OBJECTIVES

The aim of this study was to preliminarily investigate whether an enlarged geniculate ganglion fossa (GGF) on temporal bone computed tomography can diagnose GGF fracture in patients with traumatic facial paralysis by evaluating the diameter of the GGF.

MATERIALS AND METHODS

Thirty-six patients who underwent computed tomography before confirmation of GGF fracture on otologic surgery were recruited into a study group. Additionally, a cohort of 107 patients with no histories of head trauma, no structural abnormalities of inner ear, and no clinical symptoms of facial nerve disability who underwent computed tomography for other reasons were selected as a control group. The diameters of the GGFs of the study group were evaluated by two observers and compared retrospectively with those of the control group. Wilcoxon's test was used to compare discrepancies of both sides, and intraclass correlation coefficients were used to evaluate intraobserver and interobserver reliability.

RESULTS

The measurement of diameters showed good interobserver and intraobserver consistency. The discrepancy in the measurement of transdiameter between both sides of the GGF on reformatted transverse images of the study group was significantly different from that of the control group (Wilcoxon's test, P < .001). Discrepancy in the GGF on transverse images of the study group was larger than that of the control group. A significant difference existed in the discrepancy in vertical diameter between the study and control groups (Wilcoxon's test, P < .001) as well.

CONCLUSIONS

An enlarged GGF on temporal bone computed tomography offers an additional sign for the diagnosis of GGF fracture in patients with traumatic facial paralysis.

Facial nerve schwannoma of the cerebellopontine angle: a diagnostic challenge

Facial nerve schwannomas are rare lesions that may involve any segment of the facial nerve. Because of their rarity and the lack of a consistent clinical and radiological pattern, facial nerve schwannomas located at the cerebellopontine angle (CPA) and internal auditory canal (IAC) represent a diagnostic and therapeutic challenge for clinicians. In this report, a case of a CPA/IAC facial nerve schwannoma is presented. Contemporary diagnosis and management of this rare lesion are analyzed.

A rare case of greater petrosal nerve schwannoma

Background:

Facial nerve schwannomas include only 0.8% of all intrapetrous mass lesions, and schwannomas originating exclusively from the greater petrosal nerve (GPN) are extremely rare. To date, only 13 reports have been described. In this case, the tumor was thought to originate from the GPN on the basis of clinical, radiological, and operative findings.

Case Description:

A 23-year-old girl presented an acute left facial palsy, a disturbance in tear secretion of the ipsilateral eye, and a left-sided conductive hypoacusia. Computed tomography (CT) scan and magnetic resonance imaging (MRI) showed an extradural mass in the left middle fossa. A subtemporal approach was performed and the lesion, originating from the proximal portion of the GPN, was excised. The post-operative course was satisfactory, except for a xerophtalmia, which was treated with artificial teardrops.

Conclusion:

GPN schwannomas can originate anywhere alongside the course of the nerve, from its proximal segment near the facial hiatus to its distal segment near the foramen lacerum. For these reasons, it requires differential diagnosis with trigeminal nerve schwannomas or with injuries arising from the geniculate ganglion, because it can be easily confused with those lesions. However, in less severe cases, an early diagnosis can be able to preserve the function of the facial nerve by reducing iatrogenic injuries caused by surgical maneuvers.

Imaging of inflammatory and infectious diseases in the temporal bone

Inflammatory and infectious diseases of the temporal bone are a major indication to perform high-resolution CT and MR imaging studies. Such studies allow one to evaluate the extent of the disease in the soft tissues and in the bony structures of the temporal bone. On these same imaging studies the possible extension of the infection to surrounding regions is visualized. In this article a segmental approach is used, focusing on four structures in the temporal bone: the external ear, the otomastoid and petrous apex, the inner ear, and the facial nerve. For each of the four sections imaging findings are described and illustrated, and if relevant a differential diagnostic approach is highlighted.

Intraparotid facial nerve schwannoma: literature review and classification proposal

OBJECTIVE

The aim of this review was to assess and describe the pathological characteristics of intraparotid facial nerve schwannoma, in order to facilitate correct prognostic evaluation and appropriate therapeutic decision making.

STUDY DESIGN AND SETTING

The literature was reviewed regarding involvement of the various portions of the facial nerve. A classification is proposed, based on anatomical and pathological evaluations, which can supply important information on facial functional outcomes.

RESULTS

From this study, two important characteristics of facial nerve schwannoma emerged: the schwannoma may be capable of surgical dissection from the facial nerve, leaving the latter anatomically preserved; or it may be tightly bound to the nerve, in which case it must be removed along with a variable section of nerve tract, followed by reconstruction.

CONCLUSIONS

The extent of the neoplasm and the involvement of different branches of the facial nerve are very important elements to consider when evaluating prognosis and therapy.

SIGNIFICANCE

To emphasise the usefulness of a classification, based on anatomical and pathological evaluation, which can supply information about post-operative facial function.

Diagnóstico del schwannoma intracraneal del nervio facial. factores clínicos, radiológicos y valor de la inmunohistoquímica

OBJECTIVE

To analyze the clinical, radiological, and pathological features which may be useful to differentiate intracranial schwannomas of the facial nerve from vestibular schwannomas.

MATERIAL AND METHODS

A retrospective study of 91 patients undergoing surgery with a clinical suspicion of vestibular schwannoma is presented. Clinical and radiological features are analyzed. Immunohistochemistry for neurofilaments was performed in selected cases of unilateral vestibular schwannomas, bilateral vestibular schwannomas, and facial nerve schwannomas.

RESULTS

Facial function was normal in 83% of patients with vestibular schwannoma. Both patients with facial schwannomas had preoperative House-Brackmann grade II facial function. MRI showed no main differences between facial and vestibular schwannomas. A positive immunostaining was found in unilateral vestibular schwannomas, bilateral vestibular schwannomas, and facial nerve schwannomas.

CONCLUSION

There are no specific clinical, radiological, or pathological factors to accurately differentiate schwannomas of the facial nerve from vestibular schwannomas.

Fascicle preservation surgery for facial nerve neuromas involving the posterior cranial fossa

OBJECTIVE

To assess facial nerve function after fascicle preservation surgery in cases of facial nerve neuroma involving the cerebellopontine angle.

STUDY DESIGN

Retrospective case series and literature review.

SETTING

Tertiary referral center.

PATIENTS

Seven patients with facial nerve neuroma involving the posterior cranial fossa were reviewed from a single neurotologist's practice and combined with a review of 648 cases reported in the literature.

INTERVENTIONS

Translabyrinthine resection was used in all patients for complete tumor removal. Nerve reconstruction was accomplished with fascicle preservation (three cases), cable nerve interposition grafting (three cases, one of which involved using cranial nerve VIII as the graft), or direct anastomosis (one case).

MAIN OUTCOME MEASURE

Facial nerve function as measured by the House-Brackmann grading system. RESULTS A postoperative facial nerve (House-Brackmann) grade of II/VI was obtained in two of our three patients who underwent fascicle preservation reconstruction and in two of eight cases reported by other authors. One case reported elsewhere resulted in grade I/VI, and four other cases reported elsewhere achieved grade III/VI; only two cases were grade V/VI. There were no tumor recurrences at 5 to 19 years of follow-up.

CONCLUSION

Most cases of facial nerve neuroma require facial nerve resection. In rare cases, these tumors can be dissected away from the nerve fascicles, allowing the surgeon to preserve the facial nerve. This method resulted in better long-term postoperative facial nerve function (House-Brackmann grade II/VI vs. grade III/VI) compared with other techniques for patients in this small series, and no tumor recurrence.

A rare case of a facial-nerve neurofibroma in the parotid gland

The incidence of solitary neurofibroma of the facial nerve originating in the parotid region is extremely low. We report a case of a solitary neurofibroma in a 30-year-old male, who initially presented with a parotid mass without facial paresis or paralysis. A chain of small nodules had been palpable in the right parotid region for the previous 2-3 years. MRI and CT scans revealed several small ovoid lesions extending from the frontal margin of the parotid gland to the retromandibular region. The lesions were surgically removed. The main trunk of the facial nerve was adherent to the dorsal side of the largest nodule; however, this mass was resected atraumatically. Histopathological examination indicated neurofibroma. The incidence, presentation, diagnosis and surgical treatment of intraparotid neurofibroma are discussed and compared with those of Schwannoma.

Facial nerve neuromas: report of 10 cases and review of the literature

OBJECTIVE

This study reviewed the management and outcomes of facial neuromas during the past decade at our institution. The goal was to analyze differences in presentation on the basis of location of the facial neuroma, review facial nerve function and hearing preservation postoperatively, and understand the characteristics of patients with tumors limited to the cerebellopontine angle or internal auditory canal. We also report an unusual case of a facial neuroma limited to the nervus intermedius.

METHODS

Nine patients with facial neuromas and one with Jacobson's nerve neuroma underwent surgery, and total resection was accomplished in nine patients. A chart review for pre- and postoperative data was performed, after which all patients were evaluated on an outpatient basis.

RESULTS

The mean age of the patients was 47 years; mean follow-up time was 33.1 months. The most common presenting symptoms were hearing loss (six patients) and facial paresis (five patients). A total of five patients had progressive (four patients) or recurrent (one patient) facial paresis. No patient experienced worsened hearing as a result of surgery, and one experienced improvement in a conductive hearing deficit. Five patients required cable graft repair of the facial nerve; four improved to House-Brackmann Grade 3 facial paresis. Four of five patients with preserved anatomic continuity of the facial nerve regained normal facial function. There were no surgical complications. No tumors have recurred during follow-up. We report the second nerve sheath tumor limited to the nervus intermedius.

CONCLUSION

This series documents that facial neuromas can be resected safely with preservation of facial nerve and hearing function. Preservation of anatomic continuity of the facial nerve should be attempted, and it does not seem to lead to frequent recurrence. Tumors limited to the cerebellopontine angle/internal auditory canal are a unique subset of facial neuromas with characteristics that vary greatly from facial neuromas in other locations, and they are indistinguishable clinically from acoustic neuromas.

Intratemporal facial nerve neuroma: anatomical location and radiological features

OBJECTIVES

To present the imaging findings and anatomical locations of a series of 88 facial nerve neuromas from two centers over a 30-year period. We describe the salient radiological features of neuromas in each anatomical location and outline the ways in which modern imaging techniques have altered our perception of this entity.

STUDY DESIGN

A retrospective review of tumors presenting to two tertiary care referral institutions since 1970.

METHODS

The charts and available imaging of patients with the diagnosis of facial neuroma were reviewed. These patients presented to the House Ear Clinic between 1970 and 1994 and to the University of Utah Medical Center (Salt Lake City, UT) between 1986 and August 2000. We examined anatomical location to determine patterns of tumor presentation and compared the findings before and after the era of magnetic resonance imaging (MRI).

RESULTS

All segments of the facial nerve were represented. Overall, multiple-segment tumors were almost twice as common (63.6%) as single-segment tumors (36.4%). Before the advent of MRI, all segments of the nerve from the cerebellopontine angle to the tympanic portion were almost equally represented (29.5%-36.3%). After MRI, the geniculate ganglion (68.2%) and labyrinthine portion (52.3%) were by far the most commonly affected areas. Before MRI, there were, on average, 1.89 segments involved per tumor. After MRI, this average number increased to 2.57 segments per tumor. Radiologically, the high-resolution computed tomography and MRI features cannot be generalized. Rather, the imaging features depend on which segments are involved. This is because of the variation in the surrounding anatomical landscape of the facial nerve in its course through the temporal bone.

CONCLUSION

The more sensitive imaging provided by newer radiological techniques has altered our perception of facial neuroma. It has provided us with an increased ability to diagnose and fully evaluate this neoplasm preoperatively, allowing improved patient counseling and surgical planning.

Cholesterol granuloma in the middle cranial fossa: report of two cases

We report two cases of cholesterol granuloma in the middle cranial fossa. On CT the lesions appeared as a nonspecific, nonenhancing soft-tissue mass with bone erosion. On MRI they were seen as areas of high signal intensity surrounded by a low-intensity peripheral zone on both T1- and T2-weighted images. Cholesterol granuloma is thought to occur when pneumatised cells in the temporal bone become obstructed. Although this lesion usually occurs in the petrous bone, it can extend to the middle cranial fossa. The diagnosis and surgical management are discussed.

Facial nerve neuroma. Report of two cases including histological and radiological imaging studies

Unlike the acoustic neuroma, a facial nerve neuroma is an uncommon finding, even in referral clinical centers. Two cases of facial nerve neuromas are presented, with special focus on the importance of adequate radiological imaging techniques and histological characteristics of tumor specimens. Surgical modalities regarding tumor removal as well as facial nerve repair are discussed and the current world literature reviewed.