For 2 yrs have symp of ms with brain mri shown nonspecific white matter. neurologist doesn't know the cause. spinal tap normal. what other condition's mimics ms? is it vitamin deficiency? or small fiber neuropathy? confused & tired of the flare ups?

Multiple sclerosis is diagnosed based on time and space, in other words, it can be diagnosed based on clinical symptoms and number of attacks over time. The MRI and spinal tap are not necessary to make the diagnoses. MS can mimic myelopathies, myelitis, other demyelinating syndromes, rheumatologic, infectious (neurosyphilis), and vascular. Your primary care can refer you to these specialists.

About 30% of MS diagnoses are inaccurate, and "symptoms of MS" are likewise often misleading. In absence of fulfillment of the McDonald Criteria regarding MRIs and spinal fluid, you do NOT have clinically definite MS. But a couple of suggestions: do have a blood test to rule out Neuromyelitis Optica if not done yet, and consider an MRI of the spinal cord.