Intracranial tumor-to-tumor metastasis in an elderly female: An unusual case report.

Tumor-to-tumor metastasis is an extremely rare event, with only 150 reported cases in the literature. Meningioma, renal carcinoma, and tumors of the thyroid are the commonest sites of metastasis. Lung, breast, and GI-tract cancers are the most common types that undergo metastasis. Meningioma is the most common intracranial tumor as recipient of the tumor-to-tumor metastasis. Although breast carcinoma is the most common tumor to metastasize, adenocarcinoma from other organs can also spread to meningiomas, like the ovary and upper gastrointestinal (GI). We report a case of adenocarcinoma metastasis to meningioma with the possibility of primary involvement of the ovary or upper GI. A 77-year-old female patient presented to neurosurgery with episodes of multiple seizures and loss of consciousness. An MRI suggested a left frontotemporal meningioma. The patient underwent craniotomy with mass dissection. Microscopic examinations showed a dual tumor containing both components of meningioma with a metastatic adenocarcinomatous component. The tumor cells were positive for cytokeratin (CK7). Thus, the final diagnosis was made as meningothelial meningiomas (WHO grade I) with metastatic mucinous adenocarcinoma, possible primaries of the ovary or upper GI tract. The patient could not be followed up as we lost the patient a few days after surgery.