Hemangioblastoma of the Cerebellopontine Angle

CNS hemangioblastoma is a benign, vascular lesion that most frequently occurs in the cerebellum of adults and accounts for 1.5 to 2.5% of all intracranial neoplasms. Most (60–75%) occur sporadically; the remainder occurs in the context of von Hippel–Lindau’s (VHL) disease. Hemangioblastomas rarely affect noncerebellar sites of the CNS with the brain stem and spinal cord as the most common secondary sites. Supratentorial hemangioblastomas are rare and to date, only ∼132 cases of supratentorial hemangioblastomas have been reported in the literature. Despite juxtaposition to the cerebellum proper, hemangioblastomas are rarely found within the cerebellopontine angle (CPA) and the sole published series of hemangioblastomas in this location has only 23 cases.

We present the case of a 61-year-old construction engineer from China. Three years prior to presentation, she developed episodes of paroxysmal vertigo. CT at that time was interpreted as negative for any pathology and she was managed symptomatically with spontaneous resolution. Two years later, her symptoms recurred and became constant with subsequent development of severe right tinnitus. There was no hearing loss, headache, diplopia, or cranial neuropathy. Due to the persistence and severity of her symptoms, she underwent repeat evaluation and subsequently presented to our institution for second opinion and definitive management. On presentation, she was awake, alert, and fully oriented with mild gait ataxia and gaze-evoked nystagmus. Pupils were otherwise equal, round, and reactive with full extraocular muscle excursion. Hearing was intact.

MRI revealed a 2.5 × 2.8 × 2.2 cm T1 hypointense mass in the right CPA containing multiple flow voids. There was T2 heterogenous hyperintensity and a cleft suggesting an extra-axial location. There was intense, homogeneous enhancement. Digital subtraction cerebral angiogram showed vascular lesion with contribution from the right anterior inferior cerebellar artery. The differential diagnosis based on the findings included vestibular schwannoma, meningioma, hemangioblastoma among others. She was brought to the operating room where a gross total resection was achieved via a right suboccipital craniotomy and retrosigmoid approach to the CPA. She did well clinically and was discharged on the third postoperative day.

The CPA is involved in 6 to 10% of intracranial neoplasms. Vestibular schwannomas and meningiomas account for 70 to 80 and 10 to 15% of these lesions, respectively. Metastases and epidermoids are also encountered in this region. It is really important to maintain a broad differential for lesions seen in this location. Unrecognized cases of hemangioblastomas could prove catastrophic as the surgeon may then be ill-prepared for encountering the high vascularity associated. Because of the flow voids and intense enhancement, a cerebral angiogram was obtained in this case preoperatively to assess the vascular milieu of the tumor. This showed that while the lesion was likely extra-axial, the AICA contributed major blood supply and embolization was considered highly risky.

While rare, hemangioblastomas occur in the CPA and are easily mistaken for schwannomas and meningiomas which are statistically much more likely lesions to be encountered in this location. Cerebral angiogram may be useful in defining the vascular anatomy preoperatively.