It is not clear that you had stapes surgery and then diagnosed with Cochlear tumor. These are two independant issues unless I am missing something. If you had MRI, MRA or CT scan done, please share the results with me. This will give me little more information as to what is going on with your ear

Your imaging studies show a possibility of a lesion in the area of the cochlea, which can certainly produce these symptoms and a recommendation to consult with an ENT who is neuro-ontology trained.

James A. Hadley, MD, FACS

Intracochlear tumors are rare and reportable by definition. Pulsatile tinnitus is not the most common type, but most causation of pulsatile tinnitus are benign. Others not. Should see another ENT. Pulsatile tinnitus can occurs with glomus tumors and other intracranial masses. Also by just benign vascular structure on surface of cochlea. Imaging study would includes CT of temporal bone with and without contrast, MRI of the temporal bone with and without contrast.

If you had a stapedectomy, that means that you have a disease called otosclerosis, which has to do with changes of the bone structure of your ears and results in a conductive hearing loss treated by the surgery you had. However, this does not cure the disease only makes you able to hear and the disease will continue advancing with age and symptoms will include tinnitus and vertigo. A cochlea tumor or an acoustic neuroma will also give you the same symptoms along with a sensory neural hearing loss. I advise seeing an otologist in one of the large university centers for a full work-up to clearly identify the source of your problems and properly treat it.