Cerebellar Hemorrhage Secondary to Cerebellopontine Angle Metastasis From Thyroid Papillary Carcinoma-Case Report

A 63-year-old woman presented with a metastatic focus of papillary thyroid carcinoma in the cerebellopontine angle manifesting as lateral gazing nystagmus and slurred speech. Computed tomography demonstrated massive hemorrhage in the left cerebellar hemisphere. She was treated conservatively. Her symptoms resolved completely, but she experienced progressive deterioration in auditory acuity and ataxia over the next 6 months. Magnetic resonance imaging with gadolinium demonstrated an enhanced mass in the left cerebellopontine angle, and she was scheduled for elective resection of the tumor. Left retrosigmoid craniotomy was performed, and the tumor was subtotally removed except for a small amount at the junction of the trigeminal nerve and the pons. Histological examination confirmed a diagnosis of metastatic papillary thyroid carcinoma. The patient then underwent adjuvant gamma knife radiosurgery. Her clinical course was unremarkable, and her hypoacusis and ataxia resolved completely. Postoperative gallium scintigraphy revealed no residual tumor and no other systemic metastases. Hemorrhagic cerebellar metastasis from papillary thyroid carcinoma is extremely rare, but early recognition of metastatic cerebellar tumor should prompt immediate treatment to avoid the development of hearing loss, ataxia, and tonsillar herniation.