(721) Malignancy in Meninges: Critical Illness and Cancer

Introduction: Detecting malignancy in cerebrospinal fluid (CSF) is challenging and delays can lead to severe outcomes such as neoplastic meningitis, which is often fatal if undetected (Weston et al., 2011). Patients with leptomeningeal involvement have a median survival of less than three months (Clarke, 2010). This case is about a 64-year-old female with stage IV left lobular breast cancer (ER/PR+) who developed acute epileptic meningoencephalitis secondary to carcinomatous meningitis.

Description: The patient presented with altered mental status, falls, and recurrent seizures on three occasions, including once in the emergency department (ED). In the ED, she was febrile, agitated, and postictal. Due to compromised airway protection, she was intubated and given 10 mg of Ativan and 1 g of Keppra BID. A head CT scan ruled out brain metastasis and showed no acute intracranial abnormalities. Empiric vancomycin, cefepime, ampicillin, and acyclovir were started for suspected meningitis. An EEG showed severe abnormalities without specific epileptiform patterns. MRI of the brain revealed diffuse marrow replacement, suggesting osseous metastases. A lumbar puncture showed CSF positive for malignant cells consistent with her breast carcinoma.
The patient failed her first extubation trial due to poor mentation and tachypnea, necessitating re-intubation. A repeat EEG indicated severe encephalopathy and underlying convulsive tendencies, but a follow-up EEG two days later showed no seizure activity. The patient's mentation gradually improved during her hospital course, and she was extubated on day eight.

Discussion: Meningeal carcinomatosis occurs in roughly 1-5% of all solid tumors (Nguyen et al., 2023). Lobular carcinomas are more likely to metastasize to the meninges than ductal carcinomas, though only 5% of breast cancer patients develop leptomeningeal involvement (Franzoi & Hortobagyi, 2019). This case highlights the rarity of discovering lobular breast cancer cells in the CSF and their significant impact on the patient's condition and prolonged hospital stay. Early diagnosis of CNS involvement from metastatic disease is crucial for improving patient care, treatment outcomes, and ICU length of stay. Current management options include intra-CSF chemotherapy, radiotherapy, and supportive care.