LAUSR

BACKGROUND Intracranial schwannomas are rarely confined to the skull. We here report a large schwannoma localized in petrous apex which presented with intratumoral hemorrhage. CASE DESCRIPTION A 35-year-old woman with mild hearing disturbance and ear fullness underwent computerized tomography (CT) scan and magnetic resonance imaging (MRI), which demonstrated a tumor accompanied with intratumoral hematoma in the right petrous apex. Bone marrow was totally destroyed but the bone cortex was relatively preserved. Pathologic specimen showed that the tumor was composed of proliferation of elongated neoplastic cells, positive for S-100 protein, showing nuclear palisading pattern; compatible with schwannoma. The lack of any cranial nerve signs and relative preservation of canals through which cranial nerves pass suggested the neurilemma cells surrounding vessels or mismigrated fetal neurilemma cells in the petrous apex as origin of the tumor. Benign nature of the tumor and total disappearance of the symptoms, supposedly due to the spontaneous absorption of the hematoma, made the patient choose wait and watch approach. MRI studied 7 years after the diagnosis showed significant decrease of the tumor volume and disappearance of the hematoma. CONCLUSION Although it is a large intraosseous schwannoma in the petrous apex, it has benign nature, its size is reduced due to the hematoma absorption, and patient is asymptomatic. We are observing for 7 years after the diagnosis.