Cause Of Meningitis In Breast Cancer Survivor?

Question: My mother is a breast cancer patient whos cancer has been in remission for about 18 months now. All of her check ups with her oncologist has been normal. she is currently hospitalized for meningitis. She has been in the hospital now for 5 days. They have ruled out bacterial meningitis at this point but are still having difficulty finding out what is causing it. I made the mistake of googling and came across neoplastic meningitis and i see it occurs in about 5 percent of breast cancer patients. I've raised my concern in sort of a side comment to her doctor because i didnt want to freak her out and she just brushed it off. No cytology of her CSF has been ordered and doctors dont think this is necessary but shouldnt it atleast be checked out so we know its not a possibility. CSF was clear with high lymphocytes. Should I trust her doctors or should i be more concerned. My mother had stage 1 breast cancer with no metastasis and a small tumor (i believe less than 1cm). She was admitted to the hospital with crippling headaches severe back pain and vomiting that had been progressing over the course of three weeks. She has had no fever. Finally her lumbar puncture was 4 days ago and they said that nothing is happening with the samples thus far and we shouldnt expect results at all before tuesday. Does that seem like a long time. Thank you!

My mother did not have a MRI but she did have a Ct scan of her head. The explanation i was given is that because her lymphocytes are high that is more suggestive of viral disease and that other types of cells would be present in her blood work if cancer was present. This contradicts information on the internet but I am (obviously) not a doctor. Is neoplastic meningitis more common in people with more advanced cancer or who have had more advanced cancer. my mothers breast cancer was found so early with no lymphnode involvement. My mother goes for checkups with her oncologist regularly and has blood work done. If cancer was present somewhere to the point that it is metastasizing would evidence have shown up on her blood work. Finally she seems to be doing a little bit better each day. If she this was cancer would such progress be atypical?