Intracranial meningioma containing metastatic colon carcinoma

Tumour-to-tumour metastasis is a rare pathological entity. Meningioma is the most common intracranial tumour to host metastases, the majority of which arise from breast and lung cancers. We present the first report of a colonic cancer metastasis within an intracranial meningioma. A 76-year-old woman presented with a one month history of partial seizures. Her medical history included resection of an adenocarcinoma of the descending colon followed by adjuvant chemotherapy 1 year before our evaluation. Magnetic resonance imaging revealed a homogeneously enhancing lesion in the right frontal convexity. A well capsulated tumour attached to the frontal dura was surgically removed. The pathological examination demonstrated a mixture of fibrous meningioma and colloid adenocarcinoma. Possible explanations for the development of a cohesive chimeric mass of composite pathology are investigated.