Cerebellopontine angle lipoma

Cerebellopontine Angle and Internal Auditory Canal Lipomas: Case Series and Systematic Review

OBJECTIVES/HYPOTHESIS

Cerebellopontine angle (CPA) and internal auditory canal (IAC) lipomas are rare, benign tumors comprising 0.08% of all intracranial tumors and can be mistaken for other, more common lesions of the CPA/IAC such as vestibular schwannoma. The purpose of this study was to review the literature and assess the evolution of CPA/IAC lipoma diagnosis and management. In addition, we present 17 new lipomas, matching the largest known case series of this rare tumor.

STUDY DESIGN

Retrospective case series and systematic review.

METHODS

Systematic review of the literature was performed using PubMed and Google Scholar. References from identified articles were also reviewed to identify potential additional manuscripts. Manuscripts and abstracts were reviewed to identify unique cases. For the case series, the charts of all CPA/IAC lipoma patients seen at a single institution from 2006-2019 were manually reviewed. Logistic regression and chi-squared analysis were performed where appropriate.

RESULTS

A total of 219 unique lipomas have been reported in the literature, including 17 presented in this study. Surgical management has been performed in 46% of cases and has been conducted less often in recent decades, likely due to improved radiographic diagnostic capabilities and understanding of surgical outcomes. Surgical management is associated with worse neurologic outcomes (P = .002) and has become less common in recent decades. Although growth is unlikely, it has been demonstrated in patients into their 30s.

CONCLUSIONS

Accurate radiographic diagnosis is imperative for appropriate patient management, as CPA/IAC lipomas should typically be managed through observation and serial imaging whereas vestibular schwannomas and other CPA/IAC lesions may require microsurgical or radiosurgical intervention depending on growth and symptomatology. Laryngoscope, 131:2081-2087, 2021.

[Trigeminal nerve lipoma presenting with trigeminal neuralgia: case report and literature review]

Cerebellopontine angle lipomas are benign mass lesions and rarely result trigeminal neuralgia. A 61-year-old male with right-sided trigeminal neuralgia in V2 and V3 divisions without sensory disturbances is reported in the article. MRI revealed mass lesion 11´11´4 mm on the lateral pontine surface spreading to the right trigeminal nerve root entry zone. No signs of neurovascular compression were found. Microsurgical exploration of the cerebellopontine angle showed a fatty mass adherent to the brainstem with incorporation of inferior part of trigeminal nerve root. Fatty tissue resection was followed by partial sensory trigeminal rhizotomy. Histological examination identified lipoma. Postoperative MRI showed small residual tissue with minimal ischemic area near trigeminal nerve root entry zone. Mild hypoesthesia within V2 and V3 trigeminal branches occurred after surgery. Trigeminal neuralgia completely resolved, and medications were discontinued. This clinical case and literature review clearly demonstrated successful elimination of trigeminal neuralgia in patients with cerebellopontine angle lipoma after resection of mass lesion and partial trigeminal rhizotomy.

Diagnostic Dilemma: Cerebellopontine Angle Lipoma Versus Dermoid Cyst

Both lipomas and dermoid cysts of the cerebellopontine angle are rare tumors. These tumors differ in their embryological origin but share similar features on imaging. Both of these congenital lesions can be found in the cerebellopontine angle (CPA), and symptomatic clinical presentation is dictated by the location of the lesion. This paper demonstrates a unique case in which a CPA lipoma was misidentified as a dermoid cyst, leading to surgical intervention. Further, the paper provides a literature review of CPA lipomas and dermoid cysts to aid readers in further differentiating between these two unique tumors.

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.

Management of cerebellopontine angle lipomas: need for long-term radiologic surveillance?

OBJECTIVE

To date, only a very limited number of lipomas of the cerebellopontine angle (CPA) have been reported. Our objective was to examine clinical and radiologic features of CPA lipomas and determine the most appropriate management plan.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary referral center.

PATIENTS

Patients with CPA lipomas were identified through the skull base multidisciplinary meeting database.

INTERVENTIONS

Radiologic surveillance and clinical assessment.

MAIN OUTCOME MEASURES

Tumor growth, assessed through radiologic measurements on serial magnetic resonance imaging, demographics, presenting symptoms, and any correlation between weight gain and lipoma growth were among the examined factors.

RESULTS

Of the 15 patients with CPA lipomas, six were female and nine were male, with an average age at presentation of 50.2 years (range, 31.7-76.4 yr) and an average follow-up time of 51.7 months (range, 6-216 mo). The lipomas were unilateral in all cases, nine on the right (60%) and six on the left (40%) side. None of the lipomas increased in size. All patients were treated conservatively. Sensorineural hearing loss was the main presenting symptom (80%) followed by tinnitus (46.7%) and vertigo (20%). None of the patients suffered from facial nerve dysfunction. There was no correlation between weight gain and tumor growth.

CONCLUSION

CPA lipomas can be diagnosed accurately with appropriate magnetic resonance imaging techniques and be managed conservatively with safety. Cochleovestibular are the most common presenting symptoms, whereas facial nerve involvement is rare. CPA lipomas do not tend to grow and can be monitored on a less regular basis.

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.

Lipomatosis of the trigeminal nerve causing trigeminal neuralgia: case report and literature review

Cerebellopontine angle lipomas are rare and attempts at surgical excision are associated with significant morbidity. Lipomatosis of nerve, the fatty infiltration of nerves, is a distinct entity. We present a case of intractible trigeminal neuralgia caused by lipomatosis of the trigeminal nerve.

CLINICAL CASE

A 25-year-old male presented with severe right-sided trigeminal neuralgia. Imaging showed a lesion involving the trigeminal nerve with signal characteristics of fat. At surgery the lesion was found to be a fatty infiltration of the nerve itself. Surgery was therefore limited to arachnoid adhesiolysis. The patient remains symptom-free and neurologically intact to date. Correctly identifying these lesions as lipomatosis of nerve rather than lipoma of the cerebellopontine angle make it clear that even partial surgical excision will inevitably result in neurological deficit and should not be attempted. However, in the case of intractable trigeminal neuralgia we demonstrate that surgery can still play a role.

Cerebellopontine angle lipoma with extracranial extension

Lipomas of the cerebellopontine angle (CPA) are rare. A recent literature review identified only 98 reported cases of CPA lipoma. We present here a case of CPA lipoma in a 28-year-old woman who was admitted to our hospital with hearing loss in her left ear. Computed tomography scan and magnetic resonance imaging revealed a CPA mass lesion with extracranial extension around the left internal carotiol artery. The patient was operated on in the sitting position via a right suboccipital craniectomy. The intracranial part of the mass was partially removed. Histopathological examination resulted in a diagnosis of lipoma. Surgical treatment of CPA lipomas is rarely indicated, and the aim of surgery must be decompression of neural structures.

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.

Lipoma of the interpeduncular fossa: demonstration by CT and MRI

A case of intracranial lipoma located in the interpeduncular fossa of a young woman is presented. Since the patient suffers only nonspecific headache, no treatment was performed. To our knowledge this is the only which was demonstrated by magnetic resonance images (MRI) in the English language literature.

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.

Trigeminal neuralgia caused by a cerebellopontine-angle lipoma: case report

This report describes the surgical management of a rare trigeminal neuralgia caused by a cerebellopontine (CP)-angle lipoma. A 13-year-old girl presented with typical trigeminal neuralgia in the right mandibular area. Magnetic resonance imaging (MRI) disclosed a lipoma in the right CP angle. A suboccipital craniectomy revealed a lipoma around the 7th and 8th cranial nerves, but there was no apparent lipoma on the surface of the trigeminal nerve. Since the trigeminal nerve swelled only by infiltration of the lipoma, a partial rhizotomy of the involved sensory root was inevitable. The surgery relieved her neuralgia. She remained analgesic in the mandibular area.

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.

Cerebellopontine angle lipoma

A case of a cerebellopontine angle lipoma is presented with a typical clinical, audiometric and radiological features of an acoustic neuroma. The correct pre-operative diagnosis was elusive even with the aid of magnetic resonance imaging.

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.

Lesions in Meckel's cave: variable presentation and pathology

A series of 12 patients with mass lesions arising from Meckel's cave is presented. Patients' age on presentation ranged from 13 months to 71 years. Nine of the 12 patients had symptoms referable to the fifth cranial nerve, but only three complained of facial pain. The 12 patients presented eight different pathological entities, including meningioma, lipoma, schwannoma, malignant melanotic schwannoma, arachnoid cyst, neurofibroma, epidermoid tumor, and chordoma. Computerized tomography and magnetic resonance imaging were most useful in localizing the lesion to Meckel's cave. All 12 patients underwent a subtemporal approach to the lesion, and gross total removal was achieved in 11. Postoperative results were excellent with no increased neurological deficits seen 3 months postoperatively. Most patients had resolution of the cranial nerve deficits except for fifth nerve function, which was impaired in nine patients postoperatively. This series demonstrates that lesions in Meckel's cave can have a varied and unusual presentation, as well as an assortment of pathology. Total removal of lesions in this area resulted in relief of symptoms in most patients, with minimum morbidity.