Healthy, 34-year old woman, no hx of cancer, etc.have occasional vertigo,not very often.how likely to be from brain tumor?no other symptoms.

Vertigo: Greetings, vertigo by definition is a "spinning/motion" like sensation that is usually accompanied with nausea maybe even vomiting. Usually the origins is in the ear. Some forms of vertigo can come from intracranial problems -cancer fortunately only be a small percentage. More likely causes are "misplaced crystals" within the inner ear, meniere's, viral or even migraine linked. See your ENT doc.