Tumor-to-tumor metastasis of breast carcinoma to atypical meningioma: Case report and literature review

Tumor-to-tumor metastasis of breast carcinoma to intracranial meningioma is an uncommon clinical entity, with metastasis to atypical meningiomas being rarely described in the available literature. Tumor-to-tumor metastasis should be considered in patients with meningioma, with or without known malignancy, as it can alarm the presence of occult or undiscovered cancer. We present a 50-year-old female patient who was referred to our clinic, presenting with mild right-sided hemiparesis, reduced visual acuity, and signs of increased intracranial pressure. Her past medical history revealed multidisciplinary treatment of a histopathologically verified invasive ductal breast carcinoma, with present metastatic lesions in the axial and proximal appendicular skeleton. Contrast-enhanced brain MRI revealed the presence of an extra-axial supratentorial frontal left-sided brain tumor with significant peritumoral vasogenic edema. The patient underwent microsurgical tumor resection, and histopathology analysis revealed a tumor-to-tumor metastasis of breast carcinoma to grade II (atypical) meningioma. She underwent postoperative chemotherapy and radiotherapy, with no recurrence of the intracranial tumor. Our thorough literature review revealed only 55 cases of tumor-to-tumor metastasis of breast carcinoma to meningioma, and only 2 of them to atypical meningioma (excluding our case), stating the rarity of this condition. Meningiomas can serve as a potential recipient tumor for malignant tumors. Considering the increasing incidence of systemic malignancies, clinicians need to be acquainted with rare entities such as tumor-to-tumor metastasis, as it can alter the clinical course of the disease. Extensive multidisciplinary evaluation by a team of neurosurgeons, radiologists, pathologists, and oncologists is essential for choosing adequate treatment strategies and improving the overall prognosis in such rare clinical scenarios.