Osteomas arising from the internal auditory canal (IAC) and locating in the cerebellopontine angle (CPA) are rare. These tumors may cause compression of the IAC with varying degree of hearing loss, vertigo, and tinnitus but sometimes asymptomatic. Here we present a 60-year-old female patient presented with a hearing loss of sudden onset in her right ear and recurrent dizziness of whirling type. Magnetic resonance imaging and computed tomography revealed CPA osteoma arising from the porus of the IAC. Osteomas should be considered as differential diagnosis in patients with sudden hearing loss and vertigo.
Key Words: Osteoma; Cerebellopontine angle; Hearing Loss, Sudden
A 77-year-old man visited our department because of dizziness from one month ago. Dizziness was continuous and non-whirling and this type of dizziness was the first time. He also complained of tinnitus and hearing impairment of the right ear. On physical examination, he showed spontaneous left-beating horizontal and torsional nystagmus and rightward head thrust was positive. He was admitted under the first impression of right vestibular neuritis.
On inner ear MRI, there was a well-demarcated 2.5×2.3 cm sized mass of right cerebellopontine angle. This mass showed somewhat low signal intensity in both T1 and T2-weighted image and modest enhancement with Gadolinum.
And approximately 4.5×3 cm sized mass could be seen in the simple chest roentgenogram.
On chest CT, there was a poorly demarcated 3×2.5 cm sized mass in left lower lobe of lung. The patient was diagnosed as small cell lung cancer with brain metastasis by Per-Cutaneous Needle Aspiration of lung. In spite of radiotherapy and concurrent chemotherapy, he expired after 5 months.