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Clinical Problem Solving: Radiology
August 17, 2009

Radiology Quiz Case 1: Diagnosis

Author Affiliations


Arch Otolaryngol Head Neck Surg. 2009;135(8):830. doi:10.1001/archoto.2009.89-b

Lipomas are benign lesions that are believed to result from a maldifferentiation of the primitive meninx. Intracranial lipomas account for only 0.1% to 0.5% of all intracranial tumors. Most intracranial lipomas are located around the corpus callosum. Lipomas of the CPA are very rare. They may be asymptomatic and incidentally discovered on brain imaging.1They can also produce symptoms due to the involvement of neighboring nerve structures. Vestibulocochlear signs (vertigo, tinnitus, and loss of hearing) are the most frequent symptoms.2,3Facial nerve signs (hemifacial spasm and facial motor impairment) and trigeminal nerve signs (sensory loss and trigeminal neuralgia) are also common. Our patient presented with vertigo but showed signs of a CPA lesion: tremor and weakness of his right arm. These symptoms can be explained by the involvement of the vestibulocerebellar and vestibulospinal connections. The right limb tremor was episodic and usually occurred when the patient's arm was in an upright position, revealing vestibular limb ataxia. Only detailed clinical investigations revealed hearing loss, which led to further investigations: audiovestibulograms and auditory brainstem evoked potentials. The clinical presentation in this case was unique considering previous observations. Tankéré et al2reviewed 98 cases of CPA lipomas. There was a 2:1 male predominance. Nearly all cases presented with vestibulocochlear nerve involvement, whereas 80% had facial nerve findings. Tumors were bilateral in 3% of cases, 60% on the left and 37% on the right, and ranged from 1 to 26 mm in diameter. About two-thirds of the patients developed progressive hearing loss, with fewer than 50% experiencing dizziness, tinnitus, headache, trigeminal symptoms, and/or facial paresis or paralysis.2