Lipomas of the internal auditory canal and cerebellopontine angle

Abstract

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.

Cerebellopontine angle lipomas: magnetic resonance imaging findings in two cases

“…The patient signed the informed consent agreeing with the study. diSCuSSion Intracranial lipomas are rare lesions, corresponding to less than 0.1% of all intracranial tumors 3,10,11 . Some authors have suggested that lipomas are congenital malformations because their lack of cellular atypia, dysplasia and other evidences of malignancy, as well as due to the fact that they are usually associated to other malformations 4,7,11 .…”

“…These tumors can cause symptoms related to the VIII nerve involvement, such as hearing loss, tinnitus, vertigo and nausea. However, trigeminal symptoms such as neuralgia, paresthesia or headache, can also occur in patients with CPA lipomas extending to the trigeminal nerve 3,5,7,8 . Our patients presented with headache, vertigo and sensorineural hearing loss.…”

“…Due to their peculiar imaging findings, the diagnosis of intracranial lipomas is highly suggestive on the basis of imaging studies 3,5 . The CT scan demonstrates a marked hypodense nonenhancing lesion in the CPA, with attenuation characteristics similar to adipose tissue (-40 to -100 HU) 1,5,9,10 .…”

“…Vestibular schwannomas and meningiomas are the most common lesions of the cerebellopontine angle (CPA), accounting for approximately 85-90% of the tumors seen in this location 1 . Lipomas are rare at this topography, representing about 0.15% of the CPA lesions 2,3 . These tumors are maldevelopmental masses that arise from abnormal differentiation of the meninx primitiva 1,4,5 .…”

“…These tumors are maldevelopmental masses that arise from abnormal differentiation of the meninx primitiva 1,4,5 . Clinically, CPA lipomas can cause slowly progressive neurological symptoms and signs affecting cranial nerves or brain stem 3,[6][7][8] . Because these lesions usually are strongly attached to the surrounding structures, any surgical attempts of complete resection can result in neural or vascular damage, reinforcing the importance of the pre-operative imaging diagnosis [1][2][3]7,9,10 .…”