DSRCT tumor

The term polyphenotypic small round cell tumor seems most appropriate to describe the general attributes of these lesions. The desmoplastic small round cell tumor (DSRCT) is the best-recognized representative of this group. It is characterized by an EWS/WTl chimeric transcript, and is a morphologically distinctive neoplasm that is characterized by reactive fibrosis surrounding discrete nests of tumor cells (Fig. 4.15). DSRCT has a relatively complicated immunoprofile. 

An antibody to the car boxy-terminal (C-terminal) region of the WT gene (WTl) is useful in recognition of desmoplastic small round cell tumor. DSRCT shows strong nuclear staining with a C-terminal WTl antibody WT and RMS can also show nuclear reactivity for WTl.37,47,48 have observed occasional examples of... 

DSRCT harbors a characteristic translocation, t(ll 22)(pl3 ql2), with an EWS-WTl gene fusion. This can be detected by tumor karyotype and RT-PCR. 48-152,178 hybridization to detect an... 

Absence of staining for the myogenic regulatory proteins myogenin and Myo-Dl help to distinguish DSRCT from RMS and both tumors can be immunoreactive for desmin, myoglobin, and actin. 

Presence of WTl staining and the EWS-WTl gene fusion distinguish DSRCT from malignant rhabdoid tumor, which is another polyphenotypic small cell malignant neoplasm. 

The polyphenotypic immunohistochemical prohle of MRT presents challenges in the differential diagnosis, particularly with DSRCT, RMS, choroid plexus carcinoma, and epithelioid sarcoma. In particular, the absence of INIl protein in proximal-type epithelioid sarcoma, in a subset of central nervous system primitive neuroectodermal tumors without a rhabdoid phenotype and in renal medullary carcinoma, suggests the existence of a wider family of hSNP5/INIl-deficient The lack of expression of INIl protein... 

Fang X, Rodabaugh K, Penetrante R, et al. Desmoplastic small round cell tumor (DSRCT) with ovarian involvement in 2 young women. Appl Immunohistochem Mol Morphol. 2008 16 94-99. 

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