Progeny in an Inhospitable Milieu-Solitary Intraventricular Metastasis From a Triple-Negative Breast Cancer Mimicking Central Neurocytoma: Case Report and Review of Diagnostic Pitfalls and Management Strategies.

Background: Triple-negative breast cancer (TNBC) is one of the most invasive subtypes of breast cancer, with high rates of visceral metastases and recurrence. Choroid plexus metastasis from breast cancer is infrequent despite a high incidence of brain parenchymal metastasis.
Methods: We report a case of solitary metastasis to the choroid plexus from a TNBC that masqueraded as central neurocytoma, and we review the PubMed database for similar cases focusing on their diagnostic challenges and management strategies.
Results: A 28-year-old woman with a history of TNBC presented with recurrent seizures, headache, and vomiting. Imaging studies depicted a well-defined lesion in the right anterior lateral ventricle that was attached to the septum pellucidum. After an initial radiological diagnosis of central neurocytoma, she deteriorated rapidly with intraventricular hemorrhage requiring emergency transcallosal microsurgical tumor decompression. Histopathological examination and immunohistochemistry confirmed breast carcinoma as the origin of the intraventricular mass. A review of the PubMed database identified only 2 case reports of choroid plexus metastases from breast cancer reported thus far.
Conclusions: Choroid plexus metastases are exceedingly infrequent and can be mistaken for the more common central neurocytoma. The intraventricular milieu is inhospitable suggesting some extracranial carcinomas develop traits that help them to thrive in the acellular cerebrospinal fluid. Intraventricular mass lesions with a history of primary neoplasm should raise suspicion for choroid plexus metastases. A high index of suspicion despite excellent control of the primary tumor and the absence of systemic metastases is indispensable.
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