Hemangioma of Internal Auditory Canal: Systemic Review

Objective: The objective of this study was to present a review article about internal auditory canal hemangioma. Data Sources: Published English-language literatures. Review Methods: PubMed and Google scholars were systematically searched using multiple search terms. Study Selection: We included studies about internal auditory canal hemangioma. Results: 42 studies were included in this study. The results showed that most patients were male, the age of patients varied between 5 to 69 years old. Two cases were multiple familial hemangioma, while the most other cases were sporadic. Hearing loss was the most common symptoms, 37% patients had facial palsy, and 38% patients had vestibular symptoms. Since most patients had nonserviceable hearing loss so, translabrynithine approach was the most common surgical approach. Most serviceable hearing patients lost their serviceable hearing after surgery. Only one third of patients with facial palsy had improvement after surgery. Most cases had attachment to facial nerve and can be removed totally. Conclusion: we should suspect IAC hemangioma in any patient with considerable hearing loss and facial palsy with small lesion in internal auditory canal.


Introduction
Cavernous hemangioma of the internal auditory canal (IAC) is a rare disease. It comprises 10 to 20% of all central nervous vascular malformations. They are composed of large, sinusoidal, thin-walled capillary spaces that may invade the surrounding neural tissue. They can mimic the symptoms of vestibular shwannomas. We review the clinical features and the management of the IAC hemangioma [1].

Material and Methods
Literature review was conducted using PubMed (MEDLINE) and Google Scholar for English articles, the following keywords were used: internal; auditory; canal and hemangioma.

Inclusion Criteria
All internal auditory canal hemangioma articles published after 1975 were included in the study.

Results
Fourty-four studies about IAC hemangioma have been reported in PubMed (MEDLINE) and Google scholars in English literatures (Table 1). Progressive

Demographic
There were 81 patients of age ranged from 5 to 69 with majority of the patients between 20 to 50 year old. There were 57 males and 24 females in the study (Figures 1 & 2).       Two patients were managed by observation. 79 patients had a surgery, 3 of them had normal hearing, and 15 patients of them had serviceable hearing loss, while the other 51 patients had non-serviceable hearing loss (Table 3). Only 11 articles reported the postoperative clinical progress of vestibular symptoms, and all reported patients with vestibular symptoms improved. 13 patients had preoperative facial spasm, and it disappeared in all of them postoperatively. Two patients were managed conservatively, 8 patients had MFA, and 29 patients had RS approach, while the other 42 patients had TR approach (Table  4). 30 patients with facial palsy had a surgery, 11 patients of them had facial weakness improvement (Table 5). 16 patients had facial reconstruction (20%) ( Table 6). 68 patients had a limited disease to IAC, while 13 patients had disease extension

Results
Most patient were male with age ranging between 20 to 50 years old. Most patients had non-serviceable hearing loss.38% patients had vestibular symptoms, 37% patients had facial palsy, 16% patients had facial spasm. Only third patient with serviceable-hearing loss preserved their hearing abilities after surgery, third patient with facial palsy had significant improvement after surgery (acute facial palsy has a better prognosis than progressive facial palsy), and all patients with facial spasm and vestibular symptoms had a good improvement. Most cases were located primary to IAC, most cases had attachment to facial nerve and can be removed totally, and about20% of patients had facial reconstruction surgery due to advanced facial nerve involvement.

Conclusion
IAC hemangioma is a rare disease with poor outcomes prognosis, we should suspect this disease in patients with progressive hearing loss and facial palsy with small lesion in internal auditory canal vertigo and Tinnitus.

Discussion
Vestibular schwannoma is the most common tumor in IAC and the cerebellopontine angle (CPA). Other tumor lesions of CPA area include meningioma, primary cholesteatoma, facial nerve neuroma, various vascular tumors, metastatic tumors, and others. Cavernous angioma was reported rarely in the IAC. Sundares et al. reported the first case of IAC cavernous angioma in 1976. These tumors were considered to originate from the capillary bed of the epineurium nerve. Vascular steal mechanism in which the blood is taken by tumor instead of the nerve causing nerve function loss even with a small size of tumor. Histopathologically, they consist of large thin-walled blood vessels that lined by flattened endothelium, which stain positive by endothelial marker CD 31, the stroma is composed of fibrous component and has mainly myofibroblast and fibroblast that stain positive for smooth muscle actin.
Depending on nerve origin and location, these tumors can cause severe progressive or sudden sensorineural hearing loss, tinnitus, sudden or progressive facial nerve palsy, facial spasm, vertigo and disequilibrium even when they are in small size. The tumor size is usually less than 10 mm. On CT scan, IAC hemangioma appear as iso-or hyper-dense lesion with slight enhancement after intravenous administration of contrast, usually stippled calcifications could also be seen with enlargement of the IAC. On MRI, It appears as lobular and isointense in T1 and hyperintense on T2 with heterogeneous T1 post -gadolinium enhancement. The main differential diagnosis is IAC Vestibular shawanoma (Table 7). Other differential diagnosis may include meningioma, lipoma, melanoma, hamartoma, and lymphoma. Complete surgical resection with avoiding complications such bleeding is the goal of treatment. Radiotherapy may promote growth and hemorrhage, so it is not recommended. No symptomatic cases can be managed conservatively. Symptomatic case should be resected surgically. Surgical approach is depended on hearing deficit and tumor size. Translabyrinthine approach is recommended for patient with non-serviceable hearing loss. Middle fossa approach and retrosigmoid approach are recommended for patients with serviceable hearing loss. This lesion could be attached firmly with facial nerve. Since the tumor is benign and slow growing, it is advocated to perform a near total resection in case where the tumor is difficult to dissect from facial nerve [18,26,27].