Desmoplastic Small Round Cell Tumor

Desmoplastic small round cell tumor is a highly aggressive tumor that frequently occurs as multiple masses in the abdomen involving the regional lymph nodes and the lining of the abdomen and pelvis.

Desmoplastic small round cell tumor is extremely rare. This tumor predominately affects boys, usually in their second decade of life. No environmental or familial risk factors have been identified for this tumor. The most common symptoms include abdominal pain, abdominal mass and symptoms of gastrointestinal obstruction.

In addition to abdominal masses, paratesticular, ovarian, parotid gland, brain and thoracic primary tumors can also occur with this disease. The cancer most commonly spreads to the liver, lungs and bones. The cell of origin for this tumor is unclear. The tumor shows characteristics of epithelial, mesenchymal and neural differentiation. A characteristic translocation between chromosome 11 and 22 has been associated with desmoplastic small round cell tumors involving the EWS and WT1 genes. How this translocation contributes to the pathogenesis of this tumor is under active study. However, the identification of this gene abnormality has been very useful in the confirming the diagnosis of this tumor.

The overall survival rate for desmoplastic small round cell tumors is less than 20 percent. Because of diffuse involvement of the abdomen at the time of diagnosis, complete resection of this tumor is rarely possible. Effective treatment must rely upon chemotherapy and radiation therapy. Recent reports suggest that multimodal therapy including surgical debulking, radiotherapy and high dose chemotherapy may improve survival in a subset of patients with desmoplastic small round cell tumor.