Malignant triton tumor (MTT) is a relatively rare, aggressive tumor made up of both malignant

schwannoma A schwannoma (or neurilemmoma) is a usually benign nerve sheath tumor composed of Schwann cells, which normally produce the insulating myelin sheath covering peripheral nerves. Schwannomas are homogeneous tumors, consisting only of Schwann cells. ...

cells and malignant

rhabdomyoblast A rhabdomyoblast is a cell type which is found in some rhabdomyosarcomas. When found histologically, a rhabdomyoblast aids the diagnosis of embryonal, alveolar, spindle cell/sclerosing, and pleomorphic rhabdomyosarcomas; however, in a tumor, express ...

s. It is classified as a

malignant peripheral nerve sheath tumor A malignant peripheral nerve sheath tumor (MPNST) is a form of cancer of the connective tissue surrounding nerves. Given its origin and behavior it is classified as a sarcoma. About half the cases are diagnosed in people with neurofibromatosis; t ...

with

rhabdomyosarcoma Rhabdomyosarcoma (RMS) is a highly aggressive form of cancer that develops from mesenchymal cells that have failed to fully differentiate into myocytes of skeletal muscle. Cells of the tumor are identified as rhabdomyoblasts. There are four subt ...

tous differentiation. The unusual name "triton" was first used in reference to observation of supernumerary limbs containing

bone A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...

and

muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...

growing on the backs of triton salamanders after the implantation of

sciatic nerve The sciatic nerve, also called the ischiadic nerve, is a large nerve in humans and other vertebrate animals which is the largest branch of the sacral plexus and runs alongside the hip joint and down the lower limb. It is the longest and widest si ...

tissue.

Diagnosis

There are three diagnostic criteria proposed: # The tumor arises along a peripheral nerve, or in a

ganglioneuroma Ganglioneuroma is a rare and benign tumor of the autonomic nerve fibers arising from neural crest sympathogonia, which are completely undifferentiated cells of the sympathetic nervous system. However, ganglioneuromas themselves are fully diffe ...

, or in a patient with

neurofibromatosis type 1 Neurofibromatosis (NF) is a group of three conditions in which tumors grow in the nervous system. The three types are neurofibromatosis type I (NF1), neurofibromatosis type II (NF2), and schwannomatosis. In NF1 symptoms include light brown sp ...

(NF1), or has a

metastatic Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then, ...

character. # The growth characteristics of the tumor is typical for a Schwann cell tumor. # Rhabdomyoblasts arise within the body of the tumor.

Treatment

References

Bibliography

* {{cite journal, author=Stasik CJ, Tawfik, title=Malignant peripheral nerve sheath tumor with rhabdomyosarcomatous differentiation (malignant triton tumor), journal=Arch Pathol Lab Med, year=2006, issue= 12, pages=1878–81, pmid=17149968, last2=Tawfik, first2=O, volume=130, doi=10.5858/2006-130-1878-MPNSTW Nervous system neoplasia