A Novel Report of Suspected Prostate Adenocarcinoma to Orbital Roof Meningioma Metastasis.

: Tumor-to-meningioma metastasis (TTMM) is an uncommon phenomenon, in which a primary malignant tumor metastasizes to a recipient preexisting meningioma. Herein, the authors report a case of a 74-year-old man with a known history of metastatic prostate adenocarcinoma who with frontal headache and right orbital apex syndrome. Initial CT studies demonstrated a right orbital roof osseous lesion. Subsequent MRI was reported as characteristic of an intraosseous meningioma with intracranial and intraorbital extensions. A biopsy of the right orbital mass was obtained and returned a diagnosis of metastatic prostate cancer. The combination of imaging and pathologic findings suggested that the clinical scenario was overall most in keeping with a skull bone-based prostate adenocarcinoma metastasis infiltrating a preexisting meningioma. This is a rare case of TTMM in an orbit-based meningioma, presenting with an orbital apex syndrome.