Acoustic neuroma arises from the myelin sheath of the nerve formed of Schwann cells. It is commonly seen from the vestibular part of VIII cranial nerve. The function of this nerve is hearing and maintenance of the balance of the body. Acoustic neuroma is a slow-growing tumor occurring in internal acoustic meatus or at a cerebellopontine angle in the posterior cranial fossa of the skull.
Can Acoustic Neuroma Grow Quickly?
Although acoustic neuroma is a slow-growing tumor, fast growth can be seen in them. There were three types of growth patterns seen in the acoustic neuroma. The first growth pattern seen is no growth or very slow growth which apparently feels like no growth is occurring in the tumor. The second growth pattern is slow-growing tumors which is this decided by the rate of growth of the tumor and defined as the growing rate of <0.2cm/ year. The third growth pattern is fast-growing tumors with a rate of above>1cm/ year[1]. The commonly found growth patterns are first and second ones because acoustic neuroma is a tumor that grows at a very slow rate.
The third pattern type of acoustic neuroma slow-growing not common among all cases the but if found they are very dangerous and difficult to treat. These may grow in size to greater than 3 to 4 cm at a very rapid pace and can also double their volume in about 6 months[1]. The fast-growing acoustic neuroma is commonly associated with genetic causes like neurofibromatosis where these could present at a small age.
These are dangerous not because of their malignant nature but because of pressure effects exerted by the tumor on the adjacent vital structures in the brain. These type of acoustic neuroma quickly grow out of the internal acoustic meatus into the cerebellopontine angle and compresses the facial nerve traveling along with it. When they grow more than few centimeters in size they compress other cranial nerves located on the pons which includes trigeminal and abducens cranial nerves. These require immediate treatment with stereotactic radiotherapy or surgical resection to reduce the size and rate of growth of tumor; otherwise, they can easily proceed to centimeter pressure effects on the brain caused due to the large space-occupying lesion.
Can Acoustic Neuroma Stop Growing?
It is seen in the first type of growth pattern where the growth is so slow that apparently, it appears to have stopped or even stopped. These are the most common patterns of growth and it is highly likely that the patient suffering from acoustic neuroma does not know about it. Since the tumor is slow-growing it sometimes becomes so slow that people often survive a fast-growing lifetime without even experiencing any symptoms and tumor is not detected until postmortem. It is also possible that the growth of the tumor has stopped. Even the fast-growing acoustic neuroma under the surgical treatment or stereotactic radiotherapy can undergo regression and drop the pace of growth to become a slow tumor.
Conclusion
All type of growth paces is seen in acoustic neuroma ranging from no growth to rapid growth. Rapid growth acoustic neuromas can be very dangerous or even life-threatening and require treatment at the earliest. The possible treatment options include a surgical intervention to reduce or to eliminate the tumor. The other newly developed treatment option includes pointing the radiotherapy at a particular spot on the tumor to deliver a fixed amount of radiation to it; this technique is known as stereotactic radiotherapy. It is a noninvasive technique and has high precision and nearly equal success rate with lesser side effects as compared to surgical interventions whereas slow-growing or non-growing vestibular schwannomas do not require treatment usually and are kept under observation. These patients are asked to follow up in the outpatient department every six months to rule out any symptoms representing acoustic neuroma development like hearing, tinnitus, headache or other abnormalities.
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