Otolaryngology Book

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Acoustic NeuromaAka: Schwannoma

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  1. Pathophysiology
    1. Majority of lesions arise from vestibular branch CN 8
  2. Epidemiology
    1. Represents 8% of all Brain Tumors
    2. Represents 80% of posterior fossa tumors
    3. Otolaryngologists sued most on missed acoustic neuroma
  3. Signs
    1. Unilateral and persistent Tinnitus beyond 1 month
    2. Gradual unilateral Sensorineural Hearing Loss
    3. Episodic Vertigo presenting symptom in 10% of cases
  4. Diagnosis
    1. MRI brain with Internal Auditory Canals
    2. Audiology
      1. Audiometry
      2. Acoustic Reflex Testing
      3. Auditory Brainstem Testing (ABR)
    3. Electronystagmography (ENG)
      1. Abnormal in 50% of cases, but non-specific
  5. Management: Otolaryngology Referral for Surgical Excision
    1. Most otolaryngologists do not preserve hearing
    2. Hearing preservation technique has 50% success

Neurilemmoma (C0027809)

Definition (MSH)A neoplasm that arises from SCHWANN CELLS of the cranial, peripheral, and autonomic nerves. Clinically, these tumors may present as a cranial neuropathy, abdominal or soft tissue mass, intracranial lesion, or with spinal cord compression. Histologically, these tumors are encapsulated, highly vascular, and composed of a homogenous pattern of biphasic fusiform-shaped cells that may have a palisaded appearance. (From DeVita Jr et al., Cancer: Principles and Practice of Oncology, 5th ed, pp964-5)
Definition (NCI)(shwah-NO-ma)
Definition (NCI)A tumor of the peripheral nervous system that arises in the nerve sheath (protective covering). It is almost always benign, but rare malignant schwannomas have been reported.
Definition (NCI)A tumor of the peripheral nervous system composed of neoplastic Schwann cells. The vast majority of schwannomas follow a benign clinical course. Only rare cases associated with a malignant clinical course have been reported.
ConceptsNeoplastic Process (T191)
EnglishNeurilemmoma, Neurilemmomas, Neurilemoma, Neurilemomas, Neurinoma, Neurinomas, Psammomatous schwannoma, Schwannoma, Schwannomas
Spanishneurilemoma, neurimoma acustico, neurinoma, schwannoma
Parent ConceptsNeuroma (C0027858), Nerve Sheath Tumors (C0206727), Neuroendocrine Tumors (C0206754), Benign neoplasm of nerve sheath origin (C1274307), Benign nerve sheath tumor - category (C1302876), Duplicate concept (C1274013)
SourcesCSP, MSH, MTH, NCI, NDFRT, OMIM, SCTSPA, SNOMEDCT
Derived from the NIH UMLS (Unified Medical Language System)



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