Desmoplastic Small Round Cell Tumor

Desmoplastic Small Round Cell Tumor (DSRCT) is a rare and aggressive soft-tissue cancer that most often arises in the lining of the abdomen (peritoneum) of adolescents and young adults, particularly males. It is defined by a specific genetic change, a fusion of the EWSR1 and WT1 genes, and tends to form multiple tumor nodules studded throughout the abdominal cavity in a dense, scar-like (desmoplastic) tissue background.

Origin

DSRCT was first described as a distinct disease in 1989 by pathologist William L. Gerald and colleagues at Memorial Sloan Kettering Cancer Center, who recognized a pattern of small round tumor cells embedded in dense fibrous stroma. The defining EWSR1-WT1 gene fusion was identified shortly thereafter in the early 1990s.

Significance in Asbestos Context

DSRCT is important in the asbestos context primarily because it can be mistaken for peritoneal mesothelioma on imaging and even on initial biopsy. Both diseases produce multiple tumor nodules coating the abdominal lining. Getting the correct diagnosis matters enormously: DSRCT is driven by a specific gene fusion and is not caused by asbestos, while peritoneal mesothelioma is strongly linked to asbestos exposure and carries very different treatment options and legal implications. If a patient or family has been told they have peritoneal mesothelioma, confirming the diagnosis with molecular testing (to rule out DSRCT and other mimics) protects both medical decisions and any potential asbestos claim, since misdiagnosis can derail treatment and undermine a case.

Example Sentence

Before accepting the peritoneal mesothelioma diagnosis, the family asked the pathologist to run molecular testing to rule out desmoplastic small round cell tumor and other look-alike cancers.

Related Terms

Peritoneal Mesothelioma, Immunohistochemistry, EWSR1-WT1 Fusion, Differential Diagnosis, Pathology Review

Notes

• If you have been diagnosed with peritoneal mesothelioma, ask whether molecular or FISH testing for the EWSR1-WT1 fusion was performed to exclude DSRCT, especially if the patient is young (under 40) or male.
• Request a second-opinion pathology review at a mesothelioma center of excellence (such as MD Anderson, Memorial Sloan Kettering, Brigham and Women's, or the University of Chicago) before starting treatment.
• Preserve all biopsy slides, tissue blocks, and pathology reports. These are needed for both confirming the diagnosis and for any legal claim, and tissue can be sent out for additional testing if questions remain.