Intraventricular Metastases from Extracranial Solid Tumors: A Systematic Review of the Literature

Introduction: Solid intraventricular metastases (SIM) from extracranial tumors account for < 5% of all brain metastases. It’s unclear which primary solid extracranial cancers are most likely to result in SIMs and given their rarity, little is known regarding their overall management and outcomes. We performed a systematic literature review to report on these areas.

Methods: A search was performed on PubMed, MEDLINE, and Embase for studies published between database inception and October 2024 using the following keywords: (“intraventricular tumors”) AND (“metastases”). Articles published in English, focused on extracranial tumors metastasizing to the ventricles, and reported patient outcomes were included.

Results: A total of 22 patients (mean age of 56) were identified across 16 articles. The predominant types of primary cancers reported were renal cell carcinoma (RCC) (36%) and lung adenocarcinoma (23%). Others included colon (10%), and 5% each of breast, gastric, rectal and esophageal cancers. Common symptoms at presentation included headaches (70%), cognitive dysfunction (55%), and ataxia (40%). 68% had metastases to the lateral ventricles, and 27% to the fourth ventricle. 17 (77%) underwent surgical resection alone, 4 (18%) underwent resection and adjuvant radiation, and one patient (4.5%) underwent stereotactic biopsy without treatment. Patients that underwent resection alone had a median survival of 2.1 months post-resection. Of the patients that underwent resection and adjuvant radiation, one (25%) died 2.5 months post-treatment while the rest (75%) had post-treatment survival duration >1 year.

Conclusion : The most common primary cancers responsible for SIMs are RCC followed by lung adenocarcinoma. Most patients present with symptoms of elevated ICP and undergo surgical resection, with a minority also undergoing adjuvant radiation. Although unclear from the studies whether these patients died from direct progression of the SIMs, their presence appears to be associated with significant morbidity and mortality. Further research focused on these rare tumors is necessary.