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

Abstract

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

A case report of a Cerebellopontine angle lipoma revealed by vertigo

“…In 2021, Totten et al conducted a systematic review and found 219 cases of CPA/IAC lipoma in English literature. 1 The first report of a CPA lipoma dates back to 1859. 4…”

“…Conservative, nonoperative attitude in the management of CPA lipomas has become increasingly more common and is associated with significantly reduced morbidity as compared to operative management. 1 However, the surgery may be indicated in extremely rare cases for patients with severe symptoms related to compression phenomena, most of the cranial nerves. The reported data showed that total removal of the lipomas is very difficult and that surgery is associated with significant morbidity.…”

“…It rarely occurs in the intracranial compartment representing only 0.08% of intracranial tumors, and it is located in the interhemispheric fissure in approximately 45% of all intracranial lipomas. 1 , 2 Cerebellopontine angle (CPA) and the internal auditory canal (IAC) are extremely rare localizations of lipoma. Only 0.1% of tumors in the CPA tumors are lipomas.…”

Acoustic Neurinoma with Synchronous Ipsilateral Cerebellopontine Angle Lipoma: A Case Report and Review of the Literature

“…However, we could not find any research reports on the efficacy of radiation therapy in treating lipomas. There was also no mention of radiation therapy in a recent systematic review of intracranial lipomas [ 1 , 2 , 15 ].…”

Lipochoristoma of the Cerebellopontine Angle

“…Compared to imaging 7-years prior, the CPA lesion had increased in size from 10 Â 16 Â 17 mm to 16 Â 23 Â 26 mm (Figs. [1][2][3]. Over this same time interval, the patient's BMI increased by 6.1 kg/m 2 , from 19.8 to 25.9 kg/m 2 .…”