Breast carcinoma metastasized to vestibular schwannoma: a rare case of tumor-to-tumor metastasis and literature review.

Tumor-to-tumor metastasis is a well-recognized phenomenon. However, cerebellopontine angle tumor, especially vestibular schwannoma, is a rare location of metastasis, with only six cases being reported previously in English-language literature reviews. We report a case of a 57-year-old woman with underlying breast cancer (T2N3M1, stage IV) who presented with unilateral facial tics, paresthesia and hearing loss, who turned out to have vestibular schwannoma with adenocarcinoma metastasis.