Eighth nerve lipoma. Case report

Evaluating the utility of a scoring system for lipomas of the cerebellopontine angle

BACKGROUND

Cerebellopontine angle (CPA) lipomas are rare, benign, slow-growing masses. Resections are considered in symptomatic patients who are refractory to targeted medical therapies, but at those stages the lipomas have often reached considerable sizes and encompass critical neurovascular structures. The objective of this study is to develop and to evaluate the utility of a scoring system for CPA lipomas. The hypothesis is that CPA lipomas with lower scores are probably best managed with early surgery.

METHODS

The PubMed database was searched using relevant terms. Data on patient and lipoma characteristics were extracted and used to design a scoring system. CPA lipomas were stratified by scores with corresponding managements and outcomes analyzed.

RESULTS

One hundred and seventeen patients with CPA lipomas were identified and 40 CPA lipomas were scored. The remaining CPA lipomas were deficient in data and not scored. No lipomas were scored as 1. Score 2 lipomas (n = 12; 30%) most often underwent serial surveillances (n = 5; 41.6%), with the majority of symptoms remaining unimproved (n = 2; 40%). Patients with score 2 CPA lipomas treated with medical therapies (n = 3; 25%) often experienced symptom resolution (n = 2; 66.6%) (p = 0.0499). Patients with score 2 CPA lipomas undergoing surgical resections (n = 3; 25%) all experienced symptom resolution (n = 3; 100%) (p = 0.0499). Score 3 was most common (n = 16; 40%) and these lipomas were often surgically resected (n = 10; 62.5%). The majority of patients with score 3 CPA lipomas having undergone surgical resections (n = 10; 62.5%) experienced symptom improvement (n = 1; 10%) or resolution (n = 4; 40%).

CONCLUSIONS

Score 2 CPA lipomas are smaller and would be deemed non-surgical in general practice. However, our data suggest that these lipomas may benefit from either medical therapies or early surgical resections. The advantages of early surgery are maximal resection, decreased surgical morbidity, and improved symptom relief.

Interpeduncular fossa lipoma: a novel cause of oculomotor nerve palsy in childhood

Oculomotor nerve palsy is a rare finding in children and, when reported, is most frequently either congenital or acquired from postnatal trauma, infection, aneurysm, or migraine. Intracranial lipomas also represent an uncommon finding in children, and although their development is not completely understood, they are now thought to be congenital in nature. Here, we describe the case of a 23-month-old boy presenting to the emergency department with left-sided, complete, pupil-involving oculomotor nerve palsy. On magnetic resonance imaging, he was found to have an intracranial lipoma of the left interpeduncular fossa. The patient had gradual and spontaneous improvement of symptoms, with complete resolution reported at the 4-month follow-up visit. However, a second magnetic resonance image at 6 months revealed that the lipoma did not change in size. To our knowledge, intracranial lipomas have been previously reported as a possible cause of partial oculomotor nerve palsy in only one adult and have never been reported in a child. In addition, we did not find any reports of intracranial lipomas as a cause of complete, pupil-involving oculomotor palsy, although they are known to cause other cranial nerve pathology. We conclude that intracranial lipomas, although rare, should be considered in the differential diagnosis for oculomotor nerve palsy in children. Further investigation is needed to determine the true incidence of this association.

Cerebellopontine angle lipoma: a rare differential diagnosis

Intracranial lipomas in an infratentorial and extra-axial location are extremely rare. The presented case of an extensive lipoma of the cerebellopontine angle (CPA) represents 0.05% of all CPA tumors operated on in our department from 1978 to 1996. The lipoma constitutes an important differential diagnosis because the clinical management differs significantly from other CPA lesions. The clinical presentation and management of the presented case are analyzed in comparison to all previously described cases of CPA lipomas. The etiology and the radiological features of CPA lipomas are reviewed and discussed. CPA lipomas are maldevelopmental lesions that may cause slowly progressive symptoms. Neuroradiology enables a reliable preoperative diagnosis. Attempts of complete lipoma resection usually result in severe neurological deficits. Therefore, we recommend a conservative approach in managing these patients. Limited surgery is indicated if the patient has an associated vascular compression syndrome or suffers from disabling vertigo.

Lipochoristomas (Lipomatous Tumors) of the Acoustic Nerve

Context.—Lipochoristomas (lipomatous choristomas) are rare tumors of the acoustic nerve (cranial nerve VIII/vestibulocochlear nerve) within the internal acoustic canal and sometimes the cerebellopontine angle, and are histogenetically believed to be congenital malformations. Their clinically indolent behavior has recently prompted a more conservative management protocol in a quest for maximal nerve/hearing preservation. This approach contrasts sharply with that for the common internal acoustic canal/cerebellopontine angle tumors, the neuroepithelial neoplasms (acoustic schwannomas and meningiomas), which behave more aggressively and have more prominent clinical manifestations. Owing to their rarity, the clinicopathologic features of cranial nerve VIII lipochoristomas have been obtained mainly through case reports.

Objective.—We present the clinicopathologic features of 11 cases of lipochoristomas of cranial nerve VIII.

Design.—The 11 cases were documented between 1992 and 2003. We performed complete clinical reviews with histologic, histochemical, and immunohistochemical analyses of formalin-fixed, paraffin-embedded tumor samples.

Results.—The patients were 8 men and 3 women with hearing loss of the right ear (5 patients) or the left ear (6 patients). No patient had bilateral tumors. All lipochoristomas histologically possessed mature adipose tissue admixed with varied amounts of mature fibrous tissue, tortuous thick-walled vessels, smooth muscle bundles, and skeletal muscle fibers, the latter verified with immunohistochemistry.

Conclusions.—The histomorphologic and immunophenotypic evidence showed that these tumors are better characterized as choristomas than as simple “lipomas,” as they have been labeled in the past. Their overall nonaggressive clinical nature in addition to the characteristic radiologic and histomorphologic findings are important clinicopathologic features for the pathologist to recognize and differentiate, especially during frozen section evaluations, in order to direct the neurosurgeon to a more appropriate conservative therapeutic intervention.

Cerebellopontine Angle Lipomas: Report of Four Cases and Review of the Literature

OBJECTIVE:

To define the management of internal acoustic meatus and cerebellopontine angle (CPA) lipomas according to their clinical, histological, and surgical characteristics.

METHODS:

We report four new cases of CPA lipomas diagnosed in the Department of Otorhinolaryngology–Head and Neck Surgery of Hôpital Pitié-Salpêtrière and review 94 cases reported previously in the literature.

RESULTS:

Lipomas represented 0.14% of CPA and internal acoustic meatus tumors. Localization was on the left side in 59.9%, on the right side in 37%, and bilateral in 3.1% of the patients. The diagnosis was confirmed radiologically in 33 of 98 patients, surgically in 60 patients, and by autopsy in 5 patients. The most frequent associated symptoms were of cochleovestibular origin, such as hearing loss (62.2%), dizziness (43.3%), and unilateral tinnitus (42.2%). Other associated symptoms involved the facial nerve (9%) or the trigeminal nerve (14.4%). Complete resection was performed in only 32.8% of the patients with frequent cranial nerve involvement. Frequent cranial nerve involvement was seen in 95.4% of all patients. After surgery, patient symptomatology was unchanged in 9.2% of the patients, and 50% were improved; however, new postoperative deficits occurred in two-thirds of the patients. Overall, 72.2% of the patients experienced new postoperative deficits such as hearing loss (64.8%). Preservation of hearing was possible in only 26% of the patients. Only 18% of patients were improved after surgery without any new postoperative deficits.

CONCLUSION:

Preoperative diagnosis of internal acoustic meatus/CPA lipomas is based on magnetic resonance imaging. The aim of surgery in these cases is not tumor removal but cranial nerve decompression or vestibular transection, and surgery is performed only in patients with disabling and uncontrolled symptoms.

[Cerebellopontine angle lipoma: clinical case]

Lipomas of the cerebellopontine angle are extremely rare. These tumors are probably maldevelopment lesions which can cause slowly progressive neurological symptoms. Including the present case, 90 lipomas in this localization have been described in the literature. The authors report a case of cerebellopontine angle lipoma in a 44-year-old male patient who suffered right hearing loss and tinnitus during seven months. The literature concerning this rare cerebellopontine angle tumor is review. The symptoms, radiological features and surgical management are discussed.

[Lipoma of the cerebellopontine angle: case report]

Lipoma of the cerebellopontine angle is a very rare tumor. We report the case of a 14-years-old female, with left side deafness during three years, associated with headache. CT scan showed an hypodense mass, without enhancement at the cerebellopontine angle. The patient was treated surgically by left retrosigmoid approach. The lesion involved the eighth and seventh cranial nerves and only a partial removal was performed. The postoperative course was uneventful. She had no more headache; the deafness of the left side remained unchanged. Asymptomatic lipoma of the cerebellopontine angle can be treated conservatively, although those with progressive symptoms should be treated surgically, with total or partial remove based on their neurovascular involvement.

Lipomas of the internal auditory canal and cerebellopontine angle

OBJECTIVE

To evaluate lipomas of the internal auditory canal (IAC) and cerebellopontine angle (CPA).

STUDY DESIGN

Retrospective review.

METHODS

Review of a multi-institutional series of 17 lipomas of the IAC/CPA, combined with a Medline review of the 67 cases reported in the world literature.

RESULTS

This series of 17 IAC/CPA lipomas is the largest reported series to date, bringing the total number of documented cases to 84. There appears to be a nearly 2:1 male to female predominance. Sixty percent were left-sided lesions, and three were bilateral. Hearing loss, dizziness, and tinnitus were the most common presenting symptoms. Surgical resection was performed in 52 (62%) of these lesions; however, total tumor removal was accomplished in only 17 (33%), which is most likely because of the fact that these tumors tend to have a poorly defined matrix and a dense adherence to neurovascular structures. Sixty-eight percent of patients experienced a new deficit postoperatively, 11% were unchanged, and only 19% improved with no new deficit. Only one documented case of tumor growth was identified; however, the reported follow-up was short (average, less than 3 years).

CONCLUSION

With the magnetic resonance imaging techniques now available, lipomas can be reliably differentiated from other masses within the CPA and IAC, so histopathologic diagnosis is rarely necessary. Because of the potential for significant morbidity with resection of these lesions, we believe that conservative follow-up is the best treatment option for patients with these rare lesions. Surgery is indicated only when significant progressive or disabling symptoms are present.

Lipomas of the internal auditory canal

Lipomas of the internal auditory canal (IAC) are rare, benign neoplasms occurring in the third to fifth decade of life predominately in Caucasian males. Eleven cases of IAC lesions have been previously reported; we report four more. Two of four cases showed atypical findings on preoperative radiographic evaluation. These two patients had surgery. Two patients with small tumors elected for observation with close follow-up. Fat suppression of T1-weighted images on magnetic resonance imaging (MRI) offers the most precise preoperative diagnostic tool of IAC lipomas. Because of the infiltrative nature of these tumors, hearing conservation surgery is unlikely to succeed. We recommend observation for those patients with small tumors and serviceable hearing.

Hemifacial spasm resulting from cerebellopontine angle lipoma: case report

A case of hemifacial spasm associated with a cerebellopontine angle lipoma is described. Both the seventh and the eighth cranial nerves were incorporated and distorted within this tumor, which seemed to be the cause of hemifacial spasm and other cranial nerve dysfunctions, but obvious vascular elements were not included. To identify a cerebellopontine angle lesion as a lipoma is very important in surgical management. Magnetic resonance imaging is essential to the differential diagnosis of the cerebellopontine angle lesion.

Lipoma of the cerebellopontine angle. Case reports and literature review

Two patients with cerebellopontine angle (CPA) lipoma were studied. They were submitted to surgical treatment. Available literature was reviewed and 29 cases with same lesion were identified which had been treated by surgery. Clinical manifestations, possibility of diagnostic methods, surgical indications and treatment strategies are discussed. Attention is called to the peculiarities of CPA lipomas and the doubtful validity of attempting complete excision in all cases.

Lipoma of the cerebral cortex: case report

The first clinically diagnosed and successfully operated case of a symptomatic lipoma involving the cerebral cortex is reported. The patient presented with severe headaches and recurring focal seizures with secondary generalization. Computer tomography scan and magnetic resonance imaging suggested a left frontoparietal lipoma. After undergoing a craniotomy and tumor excision, the patient has shown resolution of headaches and seizures at 1-year follow-up. Lipomas of the cerebral cortex should be excised if symptomatic and accessible.

Primary intravestibular lipoma

An intravestibular lipoma was discovered during destructive surgery for disabling vertigo in a case diagnosed as delayed endolymphatic hydrops. The author recommends that in cases that resemble Meniere's disease but have unusual symptoms, the existence of other lesions within the inner ear should be suspected.

Lipoma of the sylvian region

An exceptional case of lipoma of the sylvian region is described and the other seven reported cases are reviewed. The sylvian fissure is the most rare site of intracranial lipomas. Sylvian lipomas may be asymptomatic or present with epileptic seizures due to irritation of the cortex of the sylvian fissure. Only two previous cases have been diagnosed during life by computerized tomography and operated on; the deep location of these lipomas and their adherences to the sylvian cortex and the branches of the middle cerebral artery make radical removal impossible and dangerous.

Cerebellopontine angle lipoma

Cerebellopontine angle lipomas are rare lesions that differ from other intracranial lipomas in that they typically present with slowly progressive focal signs and symptoms identical to those of other tumors of this location, and by their propensity for intimate involvement of the adjacent cranial nerves. The lipomas in this study demonstrated this tendency to splay apart and infiltrate the cranial nerves, with the fatty tissue adjacent to the nerves invariably containing portions of the cranial nerves. Hence, the dissection of the adipose tissue from the nerves led to greater than anticipated postoperative neurologic deficits. Therefore, minimal excision of tumor is recommended to achieve decompression. Since preoperative evaluation does not distinguish with certainty this lesion from others more common to this location, intraoperative examination of frozen sections is required to confirm the diagnosis.

Mesenchymal differentiation in trigeminal neurilemmoma

An unusual neurilemmoma of the trigeminal nerve in a 31-year-old woman is described. The neoplasm was roentgenographically calcified and contained various types of mesenchymal tissue, including a cavernous angioma, cartilage, bone, and adipose tissue. Angioma in combination with neurilemmoma occurs more frequently than other forms of mesenchymal tissue. Lipoma is an uncommon component of neoplasms affecting the cranial nerves. Cartilage and bone are rarely encountered in benign intracranial neurilemmomas. The histogenesis of this combined neoplasm is discussed in relation to the ectomesenchymal properties of the neural crest.