[Clinical and imaging characteristics analysis of intralabyrinthine and internal auditory canal lipomas]

Objective:To investigate the clinical and imaging characteristics of intralabyrinthine and internal auditory canal（IAC） lipomas so as to improve diagnostic accuracy. Methods:A retrospective analysis was conducted on the clinical follow-up data of 8 patients diagnosed with intralabyrinthine or IAC lipomas at our hospital from January 2017 to September 2024. The diagnostic key points and diagnosis and treatment strategies were discussed with reference to the literature. Results:The cohort comprised 4 males and 4 females, all with unilateral involvement（left: 3; right: 5）, aged 7-61 years. The predominant symptoms were unilateral sensorineural hearing loss（SNHL） with tinnitus（progressive in 5 cases, sudden in 3）. Two patients experienced vertigo. Imaging features: Temporal bone HRCT revealed fat-density lesions（HU: -30 to -100）; MRI demonstrated T1WI hyperintensity, T2WI heterogeneous signals, no contrast enhancement, and signal attenuation on fat-suppressed sequences. Lesion size ranged from 2 to 8 mm. All cases were confirmed by imaging and without surgical intervention. Follow-up duration spanned 6 months to 9 years（mean: 59.3 months）. No tumor growth was observed during follow-up; one patient exhibited worsened hearing loss and tinnitus, while the other 7 had stable symptoms. Conclusion:Imaging is definitive for diagnosing intralabyrinthine and IAC lipomas. These lipomas exhibit indolent growth, making follow-up observation the optimal clinical strategy.