BACKGROUND Jugular bulb anomalies are asymptomatic lesions commonly seen in routine practice. However, some patients with jugular bulb anomalies may present with symptoms such as tinnitus or conductive hearing loss (CHL). METHODS A 9 year old boy complained right sided hearing disturbance without any vestibular symptoms. Pure tone audiometry (PTA) revealed a mild right sided conductive hearing loss. Otoscopy showed a red-purplish mass like lesion in his right middle ear cavity, which was regarded as hypervascular tumor. METHODS Based on otoscopic findings, preliminary differential diagnoses included jugular bulb anomaly, hemotympanum, cholesterol granuloma and paraganglioma. METHODS We performed contrast enhanced computed tomography of the temporal bone (TBCT). RESULTS CT scan showed and enhancing lesion which was bulging from his right jugular foramen to the middle ear with dehiscent jugular bulb. The lesion showed the same degree of contrast enhancement with the venous vasculature. This lesion contacted with the tympanic membrane, incudostapedial joint and round window, which might be attributable to interruption of sound transmission mechanics. Otherwise there was no evidence of mass or trauma related lesions in the temporal bone. CONCLUSIONS Although most of jugular bulb anomalies are asymptomatic, patients may present with conductive hearing loss due to the interference of sound transmission mechanics.