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What is alveolar rhabdomyosarcoma?
Listen to pronunciation. (al-VEE-oh-ler RAB-doh-MY-oh-sar-KOH-muh) A soft tissue tumor that is most common in older children and teenagers. It begins in embryonic muscle cells (cells that develop into muscles in the body).
What does Parameningeal mean?
Parameningeal rhabdomyosarcomas (PM RMS) are tumors arising from sites adjacent to the meninges (nasopharynx, middle ear, paranasal sinuses, infratemporal and pterygopalatine fossa) and constitute half of all head and neck RMS cases [2], [3], [4].
What causes alveolar rhabdomyosarcoma?
Gene changes in ARMS Certain genes in a cell can be turned on when bits of DNA are switched from one chromosome to another. This type of change, called a translocation, can happen when a cell is dividing into 2 new cells. This seems to be the cause of most cases of alveolar rhabdomyosarcoma (ARMS).
Is alveolar rhabdomyosarcoma curable?
Approximately 80% of patients with low-risk rhabdomyosarcoma can now be cured of their disease.
How long can you live with alveolar rhabdomyosarcoma?
Metastatic alveolar rhabdomyosarcoma (RMS) has a poor prognosis, currently < 20% survival at 3 years.
What is desmin in a tumor?
Desmin is a smooth-muscle type intermediate filament protein, expressed by smooth muscle cells, but also found expressed in fibrotic tissue in wound healing and in tumor ‘desmoplastic’ stroma, yet the origin of the cell type expressing desmin has been controversial [16].
What is desmin immunohistochemistry?
Description: Desmin is a 53 kDa intermediate filament protein present in smooth muscle cells, striated muscle cells and myocardium. In skeletal and cardiac muscle cells, desmin filaments are localized in the Z-bands. Primary Antibody.
Is alveolar rhabdomyosarcoma rare?
Rhabdomyosarcoma is rare. Only about 500 people are diagnosed each year in the United States. Most of them are children or adolescents.
Can you survive alveolar rhabdomyosarcoma?
What does positive for desmin mean?
More than 95% of the tumor cells were desmin-positive, suggesting a muscle origin and supporting the diagnosis of RMS. Nine tumors for which the preferred first histologic diagnosis was also RMS were desmin-negative.
Where is desmin located?
Desmin is found in heart (cardiac) muscle and muscles used for movement (skeletal muscle). Within muscle fibers, desmin proteins are important to help maintain the structure of sarcomeres, which are necessary for muscles to tense (contract).
What does desmin stain for?
Atrophic skeletal muscle fibers staining with desmin. Desmin highlighting atrophic skeletal muscle fibers being infiltrated by a desmin-negative sarcoma.
What is CD99 in sarcoma?
CD99 is a cell surface glycoprotein (also known as MIC2) that is recognized by the monoclonal antibody O13. Strong, diffuse membranous expression of CD99 is seen in nearly all Ewing sarcomas (Fig. 8.6).7 CD99 expression is unrelated to the gene products of the specific translocations found in Ewing sarcomas.
Alveolar rhabdomyosarcoma is also a tumor of adolescent and young adult people. This tumor consists of sheets of uniformly small, undifferentiated round cells in which tumor cells are supported on a fibrous framework and often form alveolar-like structures because of loss of cohesiveness in the center of cell nests.
What is embryonal rhabdomyosarcoma composed of?
Embryonal rhabdomyosarcoma is composed of cells that may be either round and myoblast-like, or elongated and myotube-like (“strap cells”), and cells can be mononuclear or multinucleated. Tumors may consist entirely of one cell type or may contain a mixture of these cell types.
What is the prognosis of Ewing sarcoma with CD99 positive?
If CD99 is positive, Ewing sarcoma / PNET needs to be confirmed with additional immunohistochemical and adjunctive molecular testing as many other malignant neoplasms, including lymphoblastic leukemias / lymphomas as well as round and spindle cell sarcomas, are usually CD99 positive ( Cancer 1991;67:1886 )