Acoustic+Neuroma

Other possible signs or symptoms may include. [7] A high magnification the schwannoma is seen to be an Antoni type B schwannoma[7]. The pattern is a loose texture of cells with a honeycomb appearance. The accumulation of lipids within the cells gives it its characteristic look[7]. || Stage 2) tumor starts growing through the internal auditory canal on the brain side without touching the brain. Size is 10 to 20mm in largest dimension. Stage 3) tumor starts to come in contact with either or both the cerebellum or brainstem without pressing on them. May come in contact with facial nerves causing some facial, tongue, and soft palate paralysis. May also cause hoarse voice. Size is 20 to 35mm in largest dimension. Stage 4) Tumor can deform cerebellum and brainstem resulting in motor function problems. Can also cut off flow of cerebrospinal fluid, causing hydrocephalus which can cause coma and or death. Size is larger than 35mm in largest dimension.[5] || Late side effects that occur months after treatment. The extent of these depends on the size of the tumor and surrounding tissues treated.  - Surgery is commonly used for larger tumors that are growing quickly.  - Stereotactic radiosurgery is used to slow down or stop the growth of the tumor when surgery is not a good option. [8]  - Radiation recommended doses would be from 50-66 Gy in 1.8-2.0 Gy fractions. [1]   ||  || 2. Wolters Kluwer Health. UpToDate: Vestibular schwannoma (acoustic neuroma). October 31, 2011. Available at:[| http://www.uptodate.com/contents/vestibular-schwannoma-acoustic-neuroma]. Accessed May 24, 2012. 3. Lenhard RE, Osteen R, Gansler T. //The American Cancer Society’s Clinical Oncology//. Williston, VT: Blackwell Publishing, Inc; 2001. 4. Acoustic neuroma - radiotherapy as a treatment option. August 29, 2009. Available at: __[|http://www.acoustic-neuroma-brain-tumor.org]__. Accessed 6/1/2012 5. Acoustic neuroma size and position of tumor. Available at: __[]__. 2011. Accessed 6/1/2012 6. Kutz, JW. //Acoustic// //Neuroma//. eMedicine. 2011. Available at: []. Accessed: May 30, 2012. 7.//Acoustic Neuroma//. University of Minnesota. Available at: http://www.otopathology.com/acoustic.htm. Accessed: May 30, 2012. 8 . Acoustic neuroma. PubMed Health Web site. []. May 31, 2011. Accessed May 31, 2012. 9. Emami B, Lyman J, Brown A, et al. Tolerance of normal tissue to therapeutic irradiation. //Int J Radiat Oncol Biol Phys.// 1991;109-122. []. Accessed May 31, 2012. ||
 * **Epidemiolgy:** || Acoustic neuroma (AN), or vestibular schwannoma, is a schwannoma of the auditory nerve. They are Schwann cell-derived tumors that commonly arise from the vestibular portion the eight cranial nerve, which is the acoustic nerve. Hearing is the function of the acoustic nerve. [1] The overall incidence rate is about one per 100,000 person-years. These tumors usually affect men and women equally; however, they tend to affect middle age persons with the median age around 50. They account for approximately 8% of intracranial tumors in adults. Acoustic neuromas are rare in children. [2] ||
 * **Etiology:** || It is believed that the incidence may be increasing due to the widespread use of magnetic resonance imaging (MRI) and computed tomography (CT). Approximately 5% of patients present with bilateral acoustic neuromas and most of these are pathognomonic of neurofibromatosis (NF2). Acoustic neuromas are benign and slow growing. [3] ||
 * **Signs & Symptoms:** || The most common sign of acoustic neuroma is gradual hearing loss that is often attributed to getting older and is over looked due to the slow growth of the tumor.[1] Along with the gradual loss of hearing there may also be a ringing symptom called tinnitus that is persistent although not painful more so irritating.
 * Difficulty swallowing
 * Headaches
 * Confusion
 * Problems with balance
 * Vertigo
 * Change in taste
 * Numbness is the face (interminably) ||
 * **Diagnostic Procedures:** || CT, PETCT and MRI. MRI rendering the better of the two images due to the attenuation of the tumor verse surrounding tissue, CT without contrast will not show extent of tumor. a biopsy of the tumor can be done as well as “watchful waiting” to monitor the growth and keep track of symptoms severity. ||
 * **Histology:** || Acoustic neuromas derive from the Schwann cell perineural, which affects the nerve and occur with equal frequency on the superior and inferior branches of the vestibular nerve (rarely affects the cochlear portion of CN VIII)[6]. They arise at the junction of the central myelin produced by glial cells and peripheral myelin produced by Schwann cells (Obersteiner-Redlich zone)[6]. On light microscopy one will see zones of alternately dense and sparse cellularity called Antoni A and B areas, respectively. Acoustic neuromas will also stain positive for the S100 protein[6].
 * **Lymph node drainage:** || Since there is an absence of lymphatics in the brain, there is no lymphatic drainage due to the blood brain barrier. ||
 * **Metastatic spread:** || As acoustic neuromas are benign, no metastasis is known. Recurrence is rare but has been found due to incomplete resection[7]. ||
 * **Grading:** || The grade of a tumor is based on its aggressiveness of growth and cellular differentiation. Grade is determined by microscopic examination of tumor cells. Grade and stage give the physician an accurate description of the tumor so that they may treat it effectively. Since acoustic neuromas are benign and do not metastasize, they are graded as low or high grade. Low grade is considered when slight side effects are apparent. High grade is considered when more severe side effects like facial paralasis and motor functions are experienced. ||
 * **Staging:** || Stage 1) tumor starts compressing auditory nerve, causes unilateral hearing loss and tinnitus. A rough sizing of a stage one tumor on MRI is 0 to 10 mm in largest dimension.
 * **Radiation side effects:** || Early side effects that may last a short time after treatment:
 * dizziness
 * nausea and vomiting
 * inflammation in the mouth or throat
 * hair loss in the treatment area
 * headaches
 * decreased blood flow to the area treated
 * scarring of the area treated[4] ||
 * **Prognosis:** || An acoustic neuroma is not cancer. The tumor does not metastasize. It can grow, however, and press on important structures in the skull. If the tumor is small and slow growing you wouldn't have to treat it at all. There is potential for permanent hearing loss, and weakness or paralysis of the muscles in the face. Large tumors can build up fluid on the brain, which can be fatal. [8] ||
 * **Treatments:** || Treatment depends on the size and location of the tumor. Some doctors will recommend just observation. If they are not treated, some of these tumors can damage the nerves used in hearing, balance, and movement in the face.
 * **5/5:** || ** TD 5/5 values from Emami 1991 [9] **
 * **References:** || 1. Chao KS, Perez CA, Brady LW. //Radiation Oncology: Management Decisions//. Philadelphia, PA: Lippincott Williams & Wilkins; 2002.

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