When a hypochondriac worries about having a brain tumor due to dizziness/vertigo being only symptoms, what the chances they do have one?

Neurology consult: Brain tumors are rare on the scale of overall cancers accounting for approximately less than 2% of all cancers worldwide. Some can be primary lesions of the brain and some can be metastatic from disease in other parts of the body. A thorough Neurology evaluation can look for tell tale signs of brain disease, and if there has already been negative imaging studies, that can be a reassuring step.

Probably slim to non: Dizzyness and vertigo can be from Menier's disease. It is characterized by episodes of vertigo, low-pitched tinnitus, and hearing loss. Or it could possibly come from the neck with cervicogenic vertigo and headaches.

Same as everybody: Dizziness/vertigo can sometimes be a symptom of brain cancer, but it isn't the most common cause by a long shot. The chance of it is no better and no worse than in a non-hypochondriac. Worrying causes illness! Smile! Relax. Remember the best news of all--guaranteed to make your day: Everyday when you wake up is a good day automatically: because it means you didn't die in your sleep!