Tumor-to-tumor metastasis: breast carcinoma to meningioma.

Metastasis of breast carcinoma to meningioma is a rare phenomenon with relatively few reports in the literature, although it is the most common type of carcinoma-to-meningioma metastasis. Several factors have been implicated in the pathogenesis of these lesions, including the microenvironment and vascular network of the meningioma, expression of cell-cell adhesion molecules, local immunosuppression, and hormonal factors, including estrogen and progesterone, whose receptors have been well-characterized in these two tumor types. While histopathologic study is the cornerstone of diagnosis of these lesions, newer radiological modalities such as magnetic resonance spectroscopy and perfusion MRI have shown promise, particularly in screening patients at risk for developing these lesions. Because their detection is problematic, it is imperative that clinicians thoroughly examine tissue samples of resected meningiomas, as this may alter the patient's treatment plan and prognosis. Furthermore, as both of these neoplasms often co-occur in women with breast cancer, clinicians should be vigilant of the potential for intrameningioma metastasis when neurological involvement becomes apparent in late-stage disease. While these unusual lesions should be managed surgically, as with meningiomas, it is unclear whether proposed adjuvants such as hormonal and radiation therapy improve survival.