SPCM-02 LEPTOMENINGEAL METASTASIS AND RENAL CELL CARCINOMA

Abstract Leptomeningeal metastases (LM) are an aggressive and rare complication of renal cell carcinoma (RCC), with few cases described in the literature. Data regarding this presentation is currently limited. We describe our single center experience with patients with RCC and cerebrospinal fluid cytology confirmed LM from January 2013 to July 2024. Five cases were identified, with a median age of 51 years. Most patients had clear cell histology (4/5). LM presented with neurological symptoms in most (4/5), and included headache, cranial nerve IV and VII palsies, unilateral leg weakness, paraparesis, and urinary/bowel dysfunction. MRI revealed findings concerning for LM in both brain and spine in most patients (4/5). KPS was above 90 in 3 patients, and 50 and 60 in the other patients. Systemic disease was stable in most patients (4/5), and most were on active systemic treatment (4/5). Three patients had concomitant parenchymal metastases, in which 2 were present prior to the diagnosis of LM. Median time from RCC to LM diagnosis was 40.1 months (CI 23.3-not reached months). One patient was treated with bevacizumab followed by whole brain radiation, one with pazopanib, and one with focal radiation. One patient remains on treatment (intrathecal and intravenous nivolumab plus cabozantinib). Three patients were transitioned to hospice shortly after the diagnosis. Median survival after LM diagnosis was 3.4 months (CI 1.4- not reached months). LM from RCC is exceedingly rare. Survival following a diagnosis of LM is typically poor even with stable systemic disease, although one patient in our series continues treatment 5 months following the diagnosis. Our data provides the experience of a large cancer center in the US, and highlights some of the challenges of this rare diagnosis.