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

/schwan·no·ma/ (shwahn-o´mah) a neoplasm originating from Schwann cells (of the myelin sheath) of neurons; schwannomas include neurofibromas and neurilemomas.
granular cell schwannoma  see under tumor.

schwannoma

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

schwannoma

[shwonō′mə] pl. schwannomas, schwannomata
Etymology: Theodor Schwann; Gk, oma, tumor
a benign, solitary, encapsulated tumor arising in the neurilemma (Schwann's sheath) of peripheral, cranial, or autonomic nerves. Also called neurilemmoma, Schwann cell tumor.
enlarge picture
Schwannoma on the sole of the foot

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.

schwannoma (shwänō´mə),

schwannoma, malignant,

schwannoma

a neoplasm originating from Schwann cells (of the myelin sheath). Most occur in the skin, but they are also found in nerve trunks and roots. The Schwann cell is also a component of neurofibromas. Called also neurilemmoma.

cardiac schwannoma
single or multiple round or nodular masses on the epicardial surface or within the myocardium.
granular cell schwannoma
see granular cell tumor.

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 ?
The schwannoma is composed of bland spindle cells and is diffusely positive for S-100 protein (hematoxylin and eosin, original magnification x10).
Schwannoma, ancient schwannoma, peripheral nerve sheath tumor, pediatric patient.
Hearing preservation and facial nerve outcomes in vestibular schwannoma surgery: results using the middle cranial fossa approach.
Generalmente, la prevalencia de schwannomas es del 25-50% en la region de cara y cuello; dentro de la localizacion intraoral (1-12%),7 se pueden ver en lengua y piso de boca, zonas de mayor frecuencia, (17) seguidas por la zona de mucosa bucal y labio.
Peripheral nerve tumors that may manifest in oral cavity includes several differentials such as schwannoma (also known as neurilemmoma or peripheral nerve sheath tumor), neurofibroma, neurinoma in association with multiple endocrine neoplasia, palisaded encapsulated neurinoma, traumatic neuroma and granular cell tumor.
In a study that included 33 cases of digestive tract schwannomas, four tumours were found in the esophagus, 24 were in stomach, three in the rectum and two in the colon, while no case being reported from the small gut.
The majority of retroperitoneal schwannomas are benign in nature although malignant ones have also been reported (5).
Our case can also be considered to be among the large retroperitoneal ancient schwannomas that were reported in the literature with a size of 28X20X12 cm.
11] In our study on unenhanced T1-weighted images, schwannomas appeared isointense to slightly hypointense relative to the brain which after gadolinium infusion, revealed moderate heterogeneous enhancement.
Schwannomas (neurilemmomas) are benign tumours derived from the Schwann cells of the peripheral nerve sheath.