IntratemporaI faciaI nerve hemangiomas CLOUGH SHELTON, MD, DERALD E. BRACKMANN, MD, WILLIAM W.M. LO, MD, and JOSEPH N. CARBERRY, MD, Los Angeles, California

Facial nerve hemangiomas are benign vascular tumors that arise within the temporal bone and have a histologic appearance similar to both cavernous hemangiomas and vascular malformations. In contrast to facial nerve schwannomas,these are extraneural tumors that cause symptoms by compression and tend to produce deficits when very small In size. W e report our experience at the House Ear Clinic with 34 patients having these nonglomus intratemporal vascular tumors. Hemangiomas arising in the internal auditory canal tend to produce a progressive sensorineural hearing loss and are demonstrated with magnetic resonance imaging (MRI), whereas those at the geniculate ganglion are usually first seen with facial nerve symptoms and may require high-resolution computerized tomography (CT)for detection. Facial electromyography is helpful in establishing the diagnosis. Because of their extraneural nature, early diagnosis can permit removal of the tumor with preservation of facial nerves in some pathlts. (OTOLARYNGOL HEAD NECK SURG 1991,104:116.)

Facial nerve hemangiomas are benign, intratemporal, vascular tumors that arise adjacent to the facial nerve. The histologic appearance is similar to both cavernous hemangiomas and vascular malformations. These lesions have also been called ossifying hemangiomas because intratumoral spicules are seen both radiologically and histologically. They develop extraneurally and cause symptoms by compression.* Characteristically, severe neurologic deficits can occur when these tumors are of extremely small size. Because these tumors are extraneural, it is possible to remove the tumor and preserve facial nerves in some instances. In these patients with slowly progressive facial palsy or recurrent episodic facial paralysis, early diagnosis and treatment favorably affect the ultimate facial nerve function. However, it may be difficult to establish a diagnosis with current imaging techniques, particularly for those small tumors arising at the geniculate ganglion. In 1981, a total of 10 cases of intratemporal vascular tumors were reported from our institution, eight of which are included in the present r e ~ o r tAt . ~ that time, the tumors were classified histologically as either hem-

From the House Ear Clinic and House Ear Institute (Drs. Shelton and Brackmann), an affiliate of the University of Southern California School of Medicine, and the Departments of Radiology (Dr. Lo) and Pathology (Dr. Carberry), St. Vincent Medical Center. Presented at the Annual Meeting of the American Neurotology Society, Palm Beach, Fla., April 27, 1990. Reprint requests: Clough Shelton, MD, 2100 West Third St., Los Angeles, CA 90057. 23 I 1124514

angioma or vascular malformation. (It now appears that most of the tumors in the present series have characteristics of both histologic types.) Glasscock et al.4 reviewed 21 skull base vascular tumors previously reported in the literature and added three new cases. In their article, they stressed the need for a high index of clinical suspicion for the diagnosis of these lesionsone case was diagnosed only after surgical exploration. Mazzoni et al.5also reviewed the literature and provided two previously unreported cases. They discussed the controversy related to the origin and histologic classification of these tumors. In a recent report of seven hemangiomas of the internal auditory canal, Pappas et a1.6 pointed out that the intralesion calcium stippling seen on high-resolution computerized tomographic (CT) scans may help to establish a preoperative diagnosis. The predominant distribution of these tumors at the geniculate and in the internal auditory canal has been noted previously and was thought to result from the lush blood supply surrounding Scarpa’s ganglion and the geniculate ganglion.’ Further support for this view is provided by a recent histologic study showing a rich capillary plexus around the geniculate ganglion.’ The purpose of this report is to update our experience at the House Ear Clinic with diagnosis and treatment of these benign vascular tumors. PATIENTS AND METHODS

From 1972 through April 1990, a total of 34 patients with nonglomus intratemporal vascular tumors have been evaluated or treated at the House Ear Clinic.

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Table 1. Main initial symptoms for 34 patients with intratemporal vascular tumors, as a function of tumor location Hearing Location

loss

Internal auditory canal Geniculate ganglion Middle ear

15 1

0

117

FACIAL NERVE HEMANGIOMAS TUMOR SIZE n=32

Facial nerve abnormality

Dizziness

3 13 1

0 1 0

We retrospectively reviewed their medical records and the histologic slides. Facial nerve results 1 year postoperatively were obtained through facial nerve questionnaires’ or review of medical records. The facial nerve results were graded with the House-Brackmann scale. lo Nineteen of the 34 patients were women, and in 22 patients the tumors occurred on the right side. The average age at time of surgery was 40 years, with a range of 24 to 67 years. The majority of tumors were less than 1 cm in size, with a range of 0.3 to 3.0 cm (Fig. 1). Tumor size was not available from the medical records of two patients. RESULTS

Symptoms. The average duration of symptoms for the group was 31 months, with a range of 2 months to 21 years. Preoperative facial nerve abnormalities were present in two thirds of the patients. The majority of these abnormalities were facial palsy. However, in four patients facial function was normal, but facial twitching was present. The main initial symptoms varied with the location of the tumor (Table 1). Those tumors arising at the geniculate ganglion were initially seen with predominantly facial nerve findings. Many such patients first manifested recurrent Bell’s palsy with symptoms of several years’ duration. Typically, the return of facial function was decreased after each episode of paralysis. Those tumors in the internal auditory canal usually were first seen with a progressive sensorineural hearing loss such as an acoustic tumor, and retrocochlear findings were typically present. Facial nerve abnormalities might also be present, but tinnitus and dizziness were rare. Pathology. The majority of tumors in this series had a unique appearance. On gross examination, the tumors looked like red sponge. The histologic picture was characterized by large vascular spaces lined with thin endothelium (Fig. 2). These spaces were surrounded by thick walls filled with uniform fibrous tissue, with or without hyalinization. Intratumoral bone may be seen histologically.

0-0.5

0.6-1.0

1.1 -2.0

2.1 -3.0

CEHnM€ERS

Fig. 1. Distributionof tumor size in 32 patients with intratemporal facial nerve hernangiornas.

Two thirds of the tumors exhibited the unique appearance just described. In six of the patients, there was bone involvement. Two tumors consisted of large spaces and thin walls and were classified as true cavernous hemangiomas. In the remaining patients, the pathology was consistent with that of a benign vascular tumor, but was insufficient for further characterization. We were unable to define any relationship between the histologic appearance and the clinical behavior of these tumors. Electrical tests. Preoperative electroneuronography or electromyography was performed in 15 patients and findings were abnormal in all of them. Electroneuronography was performed in 11 patients and showed a decreased response in each case. A characteristic pattern of polyphasic voluntary motor unit activity (reinnervation), seen simultaneously with fibrillation potentials (denervation), was found in the four patients undergoing electromyography. Imaging. Although some of the tumors early in the series were diagnosed with polytomography, the majority of the recent diagnostic studies have been CT or MRI scan. MRI is effective in detecting small tumors in the internal auditory canal (Fig. 3), which tend to be more hyperintense than acoustic tumors on T2weighted images. ‘ I However, there were several small tumors at the geniculate ganglion that were not detected with MRI, but were later found on high-resolution CT scans (Fig. 4). Intratumoral calcium can be seen on CT scans (Fig. 5). None of the geniculate cases in this series were studied with gadolinium-enhanced MRI. Surgery. The surgical approach was chosen according to the location of the tumor, preoperative hearing level, and tumor size. Eighteen pati‘ents underwent a

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Fig. 2.Photomicrograph of facial nerve hemangioma shows characteristic histology. Large vascular spaces are lined with thin endotheiium and surrounded by thick walls filled with uniform fibrous tissue. (Hematoxylin and eosin stain; original magnification x 170.)

Fig. 3. MRI scan shows small vascular tumor in internal auditow canal (arrow).

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Fig. 4. High-resolutionCT scan shows small vascular tumor with honeycomb bone at geniculate ganglion (arrows).

middle fossa approach. which was combined with a mastoid approach in three of them. There were 15 translabyrinthine removals. and a transniastoid approach was used for the only middle ear tumor. A facial nerve graft was required in 1 1 patients and a primary anastomosis was performed in five. The facial nerve was preserved in the remaining IS patients. A nerve repair was more often required for those tumors at the geniculate ganglion ( 1 1 of 15) than for those in the internal auditory canal (4 of 18). Postoperative hearing. Postoperative audiometric data were available on 30 patients. Of the patients undergoing middle fossa and/or mastoid procedures. 64% had postoperative hearing preserved within 1 0 dB of the preoperative speech reception threshold and 15%

of the preoperative speech discrimination score. One patient with a middle fossa had a total postoperative hearing loss as a result of cochlear invasion by the tumor, which was found at surgery. Three patients required ossicular reconstruction after tumor resection; one had reconstruction during the initial surgery, and two had reconstruction at a second operation. All patients undergoing a translabyrinthine procedure had total postoperative hearing loss. Postoperative facial nerve function. One-year postoperative facial nerve results were available in 23 patients (Table 2 ) . As expected. most patients who required facial nerve repair achieved a House-Brackmann grade IV result. Two repairs were unsuccessful-one in a patient who later underwent a facial-hypoglossal

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Fig. 5. Gas CT cisternoaram shows intracanalicuar tumor with bone spicule (arrow).

Table 2.Postoperative facial nerve results at 1 year in patients with an lntraternporal vascular tumor (n = 23) Facial nerve status Facial nerve grade

I

II

Repaired

Intact

-

7 2

-

-

111

2

IV

8

V VI

1

-

2

-

1

anastomosis. Normal or nearly normal postoperative facial function occurred in most patients who had anatomic preservation of the facial nerve. DISCUSSION

It is obviously important to differentiate Bell’s palsy from paralysis resulting from tumor. Early diagnosis is particularly important with facial nerve hemangiomas because they are extraneural in origin and potentially can be removed with preservation of neural continuity if surgery is performed early. Characteristically, these vascular tumors can cause severe symptoms when they are small. This is in contrast to facial nerve neuromas, which may be relatively large before they produce symptoms. Because they are

small, hemangiomas are difficult to diagnose and require a high degree of clinical suspicion. The majority of these benign vascular tumors have a unique histologic appearance that is not entirely consistent with hemangioma and appear to be peculiar to the temporal bone. Classification of these tumors is still evolving. It is unclear at this time whether they represent true hemangiomas, vascular malformations, or a different benign vascular tumor. The intratumoral bone spicules seen in some tumors are thought to be formed by bone remodeling (metaplastic bone) as a reaction to the tumor.’ The calcifications may be a clue to the diagnosis, if detected on imaging studies. Those tumors in the internal auditory canal typically initially resemble acoustic tumor and are only diagnosed as hemangioma at surgery. However, unlike acoustic tumors, in which facial nerve symptoms are rare, hemangiomas in the internal auditory canal can first be seen with facial nerve abnormalities. Hemangiomas at the geniculate ganglion typically are first seen with facial palsy, which may be recurrent or slowly progressive. In some of the patients with recurrent palsy, there was successively less recovery after each episode of palsy. Because of their small size, these tumors at the geniculate ganglion are difficult to detect with standard imaging techniques. Facial nerve results are less satisfactory in those patients with long-standing partial or total paralysis, despite removal of the tumor

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and repair of facial nerves when necessary. This is probably the result of deterioration of the distal facial nerve, fibrosis of facial muscles, or lack of remaining “fire power” in the facial nucleus, and emphasizes the importance of early diagnosis. Electrical testing is helpful in establishing the diagnosis and findings were abnormal in every one of our patients. The electromyographic findings of simultaneous denervation and reinnervation are consistent with compression neuropathy (similar to carpal tunnel syndrome) and are not expected in Bell’s palsy (Gelles DB. Personal communication, 1988). Although MRI appears sufficiently sensitive for detection of intracanalicular tumors, it does not show all geniculate ganglion tumors. In a previous study, we found that 60%of geniculate ganglion vascular tumors were missed on MRI (without gadolinium).” It appears that tumors at this location may be more reliably demonstrated on high-resolution CT scans. Because none of the patients in this study underwent gadolinium infusion, we cannot comment on how it might enhance the accuracy of MRI for geniculate ganglion lesions. CONCLUSION A high index of clinical suspicion is required for the diagnosis of intratemporal vascular tumors. Electrical testing, particularly facial electromyography, may aid in establishing the diagnosis. MRI is recommended as the first study to demonstrate the tumor. If results of MRI are negative in a patient with predominantly facial nerve symptoms, high-resolution CT scanning with attention to the geniculate ganglion is advised. At this point, we cannot comment on the accuracy of gadolinium-enhanced MRI for the detection of genic-

ulate ganglion tumors. Because early surgery for these extraneural tumors offers the best chance for preservation of neural continuity, it is particularly important to evaluate those patients with a facial paralysis not typical of Bell’s palsy. REFERENCES 1. Curtin HD, Jenson JE, Baines L, May M. “Ossifying” heman-

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giomas of the temporal bone: evaluation with CT. Radiology 1987;164~831-5. Ylikoski J, Brackmann DE, Savolainen S. Pressure neuropathy of the facial nerve: a case report with light and electron microscopic findings. J Laryngol Otol 1984;98:909-14. Mangham CA, Carbeny JN, Brackmann DE. Management of intratemporal vascular tumors. Laryngoscope 1981;91:867-76. Glasscock ME, Smith PG,Schwaber MK, Nissen AJ. Clinical aspects of osseous hemangiomas of the skull base. Laryngoscope 1984;94:869-73. Mazzoni A, Pareschi R, Calabrese V. lntratemporal vascular tumors. J Laryngol Otol 1988;102:353-6. Pappas DG, Schneideman TS, Brackmann DE, Simpson LC, Chandra-Sekar B, Sofferman RA. Cavernous hemangiomas of the internal auditory canal. OTOLARYNGOL HEADNECK SURG 1989;10 1:27-32. Fisch U, Ruttner J . Pathology of intratemporal tumors involving the facial nerve. In: Fisch U, ed. Facial nerve surgery. Birmingham: Aesculapius, 1977:448-56. Balkany T, Fradis M, Jafek BW, Rucker NC. Hemangioma of the facial nerve: role of the geniculate capillary plexus. Presented at the Annual Meeting of the North American Skull Base Society, Marina del Rey, Calif., February 17-21, 1990. Brackmann DE, Barrs DM. Assessing recovery of facial function following acoustic neuroma surgery. OTOLARYNGOL HEADNECK SURC 1984;92:88-93. House JW, Brackmann DE. Facial nerve grading system. OTOLARYNGOL HEADNECKSURG1985;93:184-93. Lo WWM, Shelton C, Waluch V, et al. Intratemporal vascular tumors: detection with CT and MR imaging. Radiology 1989; 171~443-8.

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Intratemporal facial nerve hemangiomas.

Facial nerve hemangiomas are benign vascular tumors that arise within the temporal bone and have a histologic appearance similar to both cavernous hem...
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