Intraventricular metastasis from carcinoma breast masquerading as choroid plexus neoplasm: A case report

Metastatic tumors in the brain represent the most common type of intracranial neoplasm, comprising 8-10% of all brain tumors. 30% of such tumors are primarily of breast origin in females. Brain parenchymal metastasis is the more common presentation. Intraventricular spread is rare, seen in less than 5% of cases in a metastatic scenario. Here, we report a case of 41-year-old female presenting with intraventricular brain metastasis in a follow-up case of carcinoma breast. Five years post-surgery, the patient presented with complaints of headache. On evaluation, magnetic resonance imaging (MRI) brain showed an intraventricular lesion in the fourth ventricle. She was operated on for the same and the biopsy revealed a tumor with a complex papillary pattern resembling choroid plexus papilloma. On immunohistochemistry (IHC), the tumor cells were positive for cytokeratin 7 (CK7), Epithelial membrane antigen (EMA), GATA3, and mammaglobin favoring a metastasis from breast origin. Hence, a possibility of brain metastasis should be kept in mind in patients presenting with solitary ventricular masses due to the lack of definite radiological characteristics in such locations and histological overlap. Also, organ-specific IHC is a must in today's evidence-based era as is reflected in our case.