What is Alveolar Soft Part Sarcoma?
Alveolar Soft Part Sarcoma is a type of sarcoma with unique microscopic aspects make it a rare distinct tumor development in the soft tissues of the body. The tumor related to Alveolar Soft Part Sarcoma is highly angiogenic means the tumor is formed at the vessels of the body1,2.
In USA, Christopherson and his colleagues, Drs Foote and Stewart worked at Memorial Sloan-Kettering Cancer Center, New York and they first described and termed the Alveolar Soft Part Sarcoma1,2.
The characteristics features of the Alveolar Soft Part Sarcoma include
- Formation of mass in the thigh or buttock without providing any pain symptom; however, mass can form in any extremities of the body like an arm, trunk or other parts of the body.
- Surrounding tissues of the mass or tumor stretching can cause pain and that affects movement of the body or provides walking difficulty
- The progression of the mass is slow
- The nature of the mass is soft
- The site of the mass development differs with age, like in children the usual sites of mass formation are at the head, neck, tongue or orbit (socket of the eye). But in adult, the buttocks and thighs mostly affected the site.
- The tumor of the Alveolar Soft Part Sarcoma is malignant means it can spread to distant parts of the body.
- The cancerous spreading of the tumor usually extent to brain, bones, and lungs. Other included sites for development of the Alveolar Soft Part Sarcoma are the stomach, gynecological tract, and bladder.
- In advance stage, when cancerous nodules spread to the lungs often causes chest pain, coughing and fluid accumulation in the lungs (pleural effusions)
- Angiogenic nature of the tumor increases the blood flow and that can cause a perceptible blood flowing sound over the tumor, medically termed as a bruit. This sound is distinct from vascular malformation
- A headache is common symptoms are associated with brain
- Frequent fracture can occur due to bones metastases 1,3
Alveolar Soft Part Sarcoma is a rare slowly growing tumor. Only 0.2 to 1 percent represents Alveolar Soft Part Sarcoma of all types of soft tissue sarcoma. the usual nature of the Alveolar Soft Part Sarcoma is relatively indolent, but almost 79 percent of affected individuals develop metastatic disease.
Both adults and children can get affected with Alveolar Soft Part Sarcoma. The onset of the disease mainly occurs at the younger age or adolescent age group. In addition, it is also observed that females are mostly affected than males1,2.
The precise reason for the development of the Alveolar Soft Part Sarcoma is unknown. There are two identified gene involvement of the Alveolar Soft Part Sarcoma.
The involved chromosomes are chromosome 17 and X chromosome. On chromosome 17, the involve gene is alveolar soft part sarcoma critical region 1 gene and on chromosome X, the involve gene is TFE3 gene.
In Alveolar Soft Part Sarcoma, the breaking of TFE3 gene at the X chromosome and that adjoin with the chromosome 17 at ASPSCR1 gene. This adjoining of genetic material provides a fusion of ASPSCR1-TFE3 gene. The fusion of the genetic material synthesis an abnormal protein.
Experts assumed that formation of this abnormal protein can play an important role in the development of the Alveolar Soft Part Sarcoma. Further detail research requires establishing the exact etiology and pathophysiology of the involvement of this protein in the progression of Alveolar Soft Part Sarcoma3.
The confirmatory result can be obtained by performing a biopsy. A small tissue is collected from the developed mass and thoroughly study the tissue under a microscope. The core needle biopsy test is applied in the case of sufficient mass formation; but in the case of application difficulty of the core needle biopsy, then the tissue sample is collected by an incisional biopsy.
The sample of biopsy is transferred to the laboratory for testing the characteristic features and genetic involvement for confirmation of the presence of the Alveolar Soft Part Sarcoma.
Other imaging tools applied to diagnosis the Alveolar Soft Part Sarcoma are computed tomography (CT) scans or magnetic resonance imaging (MRI) scans. These tests can help to assist the detect the location of the tumor and also provide understanding that the position of the mass is removed or not.
CT scan is typical diagnostic tool applied in the case of presence of tumor in the lungs. Alveolar Soft Part Sarcoma usually not affect lymph nodes, but they affect blood vessels and reach to distant organs including lungs and other organs1,3.
Surgery and radiation therapy is applied in patients with brain metastases of the Alveolar Soft Part Sarcoma. The treatment plan is made depending upon the location of the mass, the size of the tumor and the stage of the malignancy.
The identification of the fusion of gene may provide an advance therapeutic approach in future, though for this detailed series of study require1,3,4.
Prognosis & Survival Rate
Childhood Alveolar Soft Part Sarcoma has a better prognosis and early diagnosis and right treatment and proper follow-up can provide disease-free normal survival.
Clinical trial reports showed that most of the affected individuals with proper treatment and follow-up can give more than five years of the survival rate. Early aged patient with a small sized tumor in orbit and lingual tumor also have high survival rate1,3.
- Keila Torres, Raphael Pollock, Alveolar Soft Part Sarcoma. Online available at http://sarcomahelp.org/asps.html
- A L Folpe, A T Deyrup. Alveolar soft‐part sarcoma: a review and update J Clin Pathol. 2006 Nov; 59(11): 1127–1132. doi: 10.1136/jcp.2005.031120. Online https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1860509/
- Alveolar Soft Part Sarcoma. National Organization For Rare Disorder. https://rarediseases.org/rare-diseases/alveolar-soft-part-sarcoma/
- Alveolar Soft Part Sarcoma (ASPS). sarcoma Foundation Of America; http://www.curesarcoma.org/patient-resources/sarcoma-subtypes/asps/
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