Cerebellopontine angle lipoma

Case contributed by Adan Radiology Department
Diagnosis certain

Presentation

Clinically free, there are no specific symptoms, presented with a history of RTA and head trauma.

Patient Data

Age: 30 years
Gender: Female

Non enhanced CT brain

ct

A well-defined right cerebellopontine angle (CPA) extra-axial homogeneous fat attenuation lesion measuring about 2.0 cm. No calcifications inside. There is a mild mass effect present on the right side of the brain stem, suggesting a CPA lipoma rather than a dermoid cyst. No other significant abnormality is observed.

Case Discussion

A 30-year-old female with a history of RTA. Submitted to CT and incidentally noted a homogenous, hypodense mature fat density lesion with regular margins, with attenuation values between -60 and -200 Hounsfield Units (HU) and then further submitted elective MRI (unfortunately unavailable) confirming the diagnosis and showed a well-defined right CPA extra-axial lesion of very bright T1WI and less bright T2WI signal intensity, the loss of signal on fat saturation sequences suggested that this lesion a lipoma. The lesion indenting the right side of the brain stem and inferior cerebellar peduncle. The patient did well and underwent follow-up many times and the lesion was stable for further more than 10 years.

Intracranial lipomas are rare, and if they present most frequent topography of intracranial lipomas is interhemispheric in the pericallosal region. Relatively rare are CPA lipomas and dermoid cysts. These lesions share similar clinical manifestations and imaging characteristics, which can lead to a misdiagnosis.

The accurate diagnosis of CPA lipomas is critical and has implications for clinical decision-making and management. In other words, the inaccurate radiologic diagnosis of a CPA lipoma as a dermoid cyst can lead to unnecessary surgery and increased risk of morbidity to the patient.

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