MS vs metastatic brain cancer

My 81year-old mom has been in hospital 2 weeks with no definite diagnosis for a month of confusion, increasing weakness, difficulty speaking. History of breast/lung CA 7 years ago. New CTs, spinal tap, echocardiogram, cultures all negative for infection or cancer. Brain MRI shows multiple lesions, neurosurgeon thinks are cancer even though none found in body on CT and won't do a brain biopsy. It is a "very unusual" MRI with no edema or shift. Oncologist not sure, thinks maybe MS. Mom is gradually getting worse. CVA ruled out. Neurologist is re-consulting tomorrow for possible MS. Mom has history of incontinence for 2 years, sleeping 12-18 hours a day for several years, bedridden. Tumor markers for breast/lung negative. I think she needs brain PET but they say it has to be done outpatient or Medicare won't pay. Is this true? Do you think she could have a diagnosis of MS at this age? What should I do?

[Abhijeet Deshmukh, MD]

Hello.

The common age range of diagnosis of MS is 20 - 50 years. But MS has been diagnosed in old age also.

The MRI picture has created the confusion. Can you mention if the MRI was T2 weighted ? MS lesions are subcortical and usually periventricular. The metastatic cancer lesions are typically on the grey matter / white matter junction.

Can you narrate the MRI results if you have a copy ?

Regards