INNV-01. THE CASE OF LEPTOMENINGEAL CARCINOMATOSIS RELATED HYDROCEPHALUS MANAGED WITH SYSTEMIC AND INTRATHECAL CHEMOTHERAPY

INTRODUCTION Leptomeningeal carcinomatosis (LC) is an end-stage sequela of metastatic cancer that commonly leads to severe neurological symptoms due to hydrocephalus and commonly treated with surgery or radiation. As these procedures are invasive and have associated risks, chemotherapy could be a great alternative. We report a case of a hydrocephalus related to LC in a patient with Stage IV breast cancer that resolved after the administration of HD-MTX and intrathecal cytarabine. CASE A 64-year-old right-handed woman with Stage IV ER positive, PR positive, HER2 negative invasive lobular carcinoma of the left breast on chemotherapy with palbociclib and alpelisib who presented with mild occipital headaches, diplopia and imbalance. Imaging revealed an extensive abnormal leptomeningeal enhancement withing the posterior fossa compatible with leptomeningeal carcinomatosis. CSF cytology was consistent with metastatic adenocarcinoma. Liquid biopsy detected circulating tumor cells. During the admission for the cycle 1 of systemic chemotherapy with HD-MTX and intrathecal cytarabine, neurological status deteriorated as she became stuporous due to the newly developed moderate obstructive and communicating hydrocephalus. Surgical innervation was considered but given her response to serial Ommaya taps and dexamethasone, we proceeded with observation. Symptomatic improvement was noted within few days and confirmed on imaging showing the resolution of previously seen hydrocephalus. DISCUSSION This case highlights the role of non-invasive combination of systemic and intrathecal chemotherapy in patients with LC-related hydrocephalus aimed to preserve patient’s quality of life. No relevant disclosures.