Desmoplastic small-round-cell tumor

Desmoplastic small-round-cell tumor (DSRCT) is a rare, highly aggressive and malignant tumor that primarily occurs as a mass in the abdomen.

Epidemiology

DSRCT predominantly affects adolescents and young adults, with a higher incidence in males. The exact prevalence of DSRCT is unknown due to its rarity, but it is estimated to account for less than 1% of all sarcomas.

Pathophysiology

DSRCT is characterized by the presence of small, round, blue cells in a desmoplastic stroma. The tumor is thought to originate from primitive mesenchymal cells, although the exact cell of origin is still a subject of debate. The hallmark of DSRCT is a specific chromosomal translocation, t(11;22)(p13;q12), which results in a fusion of the EWSR1 gene on chromosome 22 and the WT1 gene on chromosome 11.

Clinical Presentation

Patients with DSRCT typically present with abdominal pain, distension, or a palpable mass. Other symptoms may include anorexia, weight loss, and ascites. Due to the aggressive nature of the tumor, most patients have widespread metastasis at the time of diagnosis, most commonly to the liver, lungs, and bones.

Diagnosis

The diagnosis of DSRCT is based on histopathological examination of the tumor, which shows small, round, blue cells in a desmoplastic stroma. Immunohistochemistry is used to confirm the diagnosis, with the tumor cells typically showing positivity for desmin, vimentin, and neuron-specific enolase. The presence of the EWSR1-WT1 fusion gene can be detected by fluorescence in situ hybridization (FISH) or reverse transcription polymerase chain reaction (RT-PCR).

Treatment

The treatment of DSRCT is challenging due to its aggressive nature and resistance to therapy. Treatment options include surgery, chemotherapy, and radiotherapy. Despite aggressive treatment, the prognosis of DSRCT is poor, with a 5-year survival rate of less than 20%.

Research Directions

Current research is focused on understanding the molecular mechanisms underlying the development and progression of DSRCT, with the aim of developing targeted therapies. Clinical trials are ongoing to evaluate the efficacy of novel treatments such as immunotherapy and molecularly targeted therapy.