schwannoma


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schwannoma

 [shwah-no´mah]
1. a neoplasm originating from Schwann cells of neurons; schwannomas include neurofibromas and neurilemomas.

schwan·no·ma

(shwah-nō'mă),
A benign, encapsulated neoplasm in which the fundamental component is structurally identical to the syncytium of Schwann cells; the neoplastic cells proliferate within the endoneurium, and the perineurium forms the capsule. The neoplasm may originate from a peripheral or sympathetic nerve, or from various cranial nerves, particularly the eighth cranial nerve; when the nerve is small, it is usually found (if at all) in the capsule of the neoplasm; if the nerve is large, the schwannoma may develop within the sheath of the nerve, the fibers of which may then spread over the surface of the capsule as the neoplasm enlarges. Microscopically, schwannoma is composed of combinations of two patterns, Antoni types A and B, either of which may predominate in various examples of schwannomas.
See also: neurofibroma.
[Theodor Schwann + -oma]

schwannoma

(shwä-nō′mə)
n.
A benign, encapsulated tumor of the peripheral nerve sheath, composed almost entirely of Schwann cells.

schwan·no·ma

(shwah-nō'mă)
A benign, encapsulated neoplasm in which the fundamental component is structurally identical to a syncytium of Schwann cells; the neoplastic cells proliferate within the endoneurium, and the perineurium forms the capsule. The neoplasm may originate from a peripheral or sympathetic nerve, or from various cranial nerves, particularly the eighth nerve; when the nerve is small, it is usually found (if at all) in the capsule of the neoplasm; if the nerve is large, the neurilemmoma may develop within the sheath of the nerve, the fibers of which may then spread over the surface of the capsule as the neoplasm enlarges. Microscopically, neurilemmoma is composed of combinations of two patterns, Antoni types A and B, either of which may be predominant.
See also: neurofibroma
Synonym(s): neurilemmoma.
[Theodor Schwann + -oma]

Schwannoma

A tumor derived from the cells of the myelin sheath that surrounds many nerve cells.
Mentioned in: Acoustic Neuroma

Schwann,

Theodor, German histologist and physiologist, 1810-1882.
Schwann cell unit - a single Schwann cell and all of the axons lying in troughs indenting its surface.
Schwann cells - cells of ectodermal (neural crest) origin that compose a continuous envelope around each nerve fiber of peripheral nerves. Synonym(s): neurilemma cells
Schwann tumor
Schwann white substance - the lipid material present in the myelin sheath of nerve fibers; the medulla of bones and other organs.
schwannoma - Synonym(s): neurilemoma; neuroschwannoma
sheath of Schwann - a cell that enfolds one or more axons of the peripheral nervous system. Synonym(s): neurilemma

schwan·no·ma

(shwah-nō'mă)
A benign, encapsulated neoplasm in which the fundamental component is structurally identical to a syncytium of Schwann cells.
Synonym(s): neurilemmoma.

Patient discussion about schwannoma

Q. Anybody familiar with schwannoma?

A. A schwannoma is a kind of tumor originating from the Schwann cells. The insulating myelin sheath which covers peripheral nerves is produced by the Schwann cells. Hence, one kind of tumor originating from the Schwann cells is called a schwannoma.

Schwannomas are very homogeneous tumors consisting only of Schwann cells. The tumor cells always stay on the outside of the nerve, but the tumor itself may either push the nerve aside and/or up against a bony structure (thereby possibly causing damage). Schwannomas are relatively slow growing. For reasons not yet understood, schwannomas are mostly benign and less than 1% become malignant (degenerate into cancer). This form of cancer is known as malignant peripheral nerve sheath tumour or malignant Schwannoma or neurofibrosarcoma.

Schwannomas can arise from a genetic disorder called neurofibromatosis.

More discussions about schwannoma
References in periodicals archive ?
Current strategies in management of intracanalicular vestibular schwannoma. Curr Opin Otolaryngol Head Neck Surg 2011;19:335-40.
Melanotic schwannoma is most often solitary and round or ovoid, but multifocal tumors may be seen.
The geniculate ganglion is the most common region affected by facial nerve schwannomas [9] and has been previously reported in a patient with intermediate neuron schwannoma that also affected the facial nerve [2].
The word schwannoma is not usually associated with either the optic nerve or neurofibromatosis type 1.
All patients were operated on for Schwannomas located in the upper extremity between 2014 and 2016.
Histopathological examination of the surgical sample revealed a multi-cystic schwannoma (Figures 4, 5).
Schwannoma, neurofibroma, and granular cell tumors are their subtypes.
Nawabi and Sinisi [4] in their series of 25 patients of a similar presentation showed that the mean time to diagnose the schwannoma was 86.5 months.
Sinonasal schwannoma contributes about 4% of head and neck schwannomas [8].
Schwannoma Similar to Positive: Neurofibroma but Neurofilament, S100 characteristic Verocay Bodies with nuclear palisading, Antoni A & B areas Nodular Fasciitis Fibroblasts with Positive: SMA, vesicular nuclei in vimentin, Negative: myxoid stroma.