Tumor-to-tumor metastasis describes the ability of primary tumors to metastasize to other primary tumors. These events generally occur in aggressive and widely-metastatic disease, with the appropriate management and significance of these events unknown. A 56-year-old woman with a history of bilateral, localized, invasive lobular breast carcinoma treated with surgery, systemic therapy, and adjuvant radiation presented five and two years post-treatment with progressive neurological symptoms. Imaging revealed an intracranial meningioma, and the patient underwent resection. Pathology revealed metastatic invasive lobular carcinoma cells within the resected meningioma, and the patient was treated with postoperative radiation without sequelae. Subsequent staging scans revealed a single osseous lesion suggestive of oligometastatic disease, and the patient was promptly started on systemic therapy.
Keywords: Case report; breast neoplasms; meningioma; neoplasm metastasis.