An acoustic neuroma is a brain tumor that grows slowly and can cause a variety of symptoms that usually correspond to its size: small or large, or somewhere in between.

And that’s usually. Not always.

“The variability in presenting symptoms for an acoustic neuroma can be surprising,” says Ted McRackan, MD, MSCR, Director, Skull Base Center; Assistant Professor, Department of Otolaryngology – Head and Neck Surgery, Medical University of South Carolina.

“I have had patients with very large tumors with normal hearing and only mild balance complaints, and patients with smaller tumors with no hearing and severe imbalance,” explains Dr. McRackan.

A paper in The Laryngoscope (Volume 103, Issue 3) states: Emphasis is placed on the fact that even a small tumor has the potential to produce sudden hearing loss.

Dr. McRackan continues, “I would say, however, that larger tumors tend to have worse hearing and more balance complaints as opposed to smaller tumors.

“If the tumor becomes very large, patients can have decreased sensation of the face, difficulty walking, be lethargic and occasionally have facial weakness.”

More than Just Hearing and Balance

The shape and location of this benign brain tumor can influence the type of symptoms.

For instance, a small acoustic neuroma that’s pressing against the facial nerve is more likely to cause numbness or weakness in the face than is a big tumor that, just by chance of its location and shape, is not pressing on any nerves.

The direction of its proliferation is another influencer of the type of symptoms.

If the mass begins encroaching upon the brainstem, this can result in hydrocephalus or a disturbance in heart rhythm.

An even larger tumor, however, that’s located away from the brainstem won’t necessarily be pressing into it, and hence, won’t cause those two symptoms.

The symptoms of hearing loss, tinnitus (subjective hearing of sound in an ear) and balance problems are commonly reported.

But an acoustic neuroma – whether small, medium or large – can cause so many more symptoms.

• Clogged feeling in one ear
• Dizziness
• Headache
• Facial weakness, paralysis or pain
• Vision problems
• Swallowing and speech difficulties

Size Categories of Acoustic Neuroma

• Small is under 1.5 cm.
• Medium is 1.5 to 2.5 cm.
• Large is more than 2.5 cm.

Source: onlinelibrary.wiley.com/doi/abs/10.1288/00005537-199303000-00011