A Case of Cerebellopontine Schwannoma Presenting with a ‘Biphasic’ Hemorrhage: Case Report and Review of the Literature

Introduction: Neurinomas are benign, usually encapsulated tumors growing in peripheral nerve sheath with a high incidence in the cerebellopontine angle (CPA). We report a case of CPA schwannoma presenting with a 'biphasic' pattern of bleeding.

Methods: A 65-year-old woman came to our attention with cephalalgia and oral rhyme shift. Neurological examination showed n VII impairment and left hypacusis. A CT scan revealed a 3-cm, high-density, tumoral mass occupying the cistern of the left CPA with compression on adjacent cerebellar parenchyma. Magnetic resonance imaging focused on a round shaped lesion with a patchy pattern composed of 3 signals with different intensity, which is an expression of two-phase bleeding. Cerebral angiography ruled out the presence of AVMs and pathological vascularization. The patient underwent surgery, and the lesion was totally removed.

Results: Macroscopically, the tumor appeared as a soft, grayish mass surrounded by multiple clots. Histological examination confirmed diagnosis of vestibular schwannoma. Areas with cystic degeneration and intratumoral hemorrhage with hemosiderin-laden macrophages were observed. Unfortunately, the patient because of preexisting causes not related with the surgical treatment.

Discussion: From a review of the literature, we found that hemorrhagic vestibular schwannoma is a rare event. The first case of hemorrhagic vestibular schwannoma was reported by McCoyd et al in 1974 followed by, at most, by 35 cases. According to the literature, two-phase bleeding is atypical. We hypothesize different mechanisms that could explain such an uncommon event.