CN-13 * RECURRENT ASEPTIC MENINGITIS IN PATIENTS WITH METASTATIC BRAIN TUMORS; A NOVEL PERSPECTIVE

Meningitis due to infectious or neoplastic infiltration is a commonly considered differential diagnosis in metastatic brain tumor patients presenting with altered mentation. However, aseptic meningitis, a disease marked by CSF pleocytosis, elevated protein, sterile cultures and negative cytology is rarely encountered. Aseptic meningitis has been described in benign CNS neoplasms that occur in the vicinity of ventricles, such as dermoid and epidermoid cysts. It has been postulated that rupture of a cystic CNS tumor nearby ventricles leads to leakage of neoplastic content into the CSF resulting in aseptic meningitis. A similar process has not been described in metastatic brain tumor patients. Here, we present a case of recurrent aseptic meningitis due to leakage of necrotic and neoplastic content into CSF in a patient with brain metastasis. 62 year old male presented with progressive aphasia 6 months after diagnosis of squamous cell lung cancer. Imaging revealed a left temporal lobe brain metastasis. Radiation therapy provided minimal improvement. Upon symptom progression, imaging favored radiation necrosis and bevacizumab was initiated with no improvement. On further deterioration, his CSF profile was consistent with aseptic meningitis with further spontaneous clinical improvement. He later presented with worsening symptoms and his repeat imaging showed enlargement of the previously noted left temporal mass with communication with the posterior temporal ventricle. A repeat CSF was consistent with recurrent aseptic meningitis. The patient underwent a left temporal craniotomy. The surgeon encountered liquid necrotic material at a depth of 5 mm and wide-open ventricles with easily discernable choroid plexus. Pathologic examination revealed mostly necrosis with some cancerous tissue. The patient continued to decline without recurrence of the meningitis and expired. This case signifies the importance of considering the leakage of necrotic tissue into subarachnoid space as the cause of recurrent aseptic meningitis in patients with cranial tumors close to the ventricles.