Background: Desmoplastic small round cell tumor (DSRCT) is a recently described neoplasm. This entity is well defined, with distinct clinical, pathologic and immunohistochemical features. Molecular studies have shown a specific reciprocal translocation t(11;22)(p13;q12). To our knowledge, no report of DSRCT with molecular confirmation on cytologic material has been reported before.
Case: Fine needle aspiration (FNA) was performed on an intraabdominal mass in a 37-year-old man. A May-Grunwald-Giemsa-stained preparation showed clusters of small round tumor cells associated with desmoplastic stromal cells, highly suggestive of DSRCT. FNA of a supraclavicular node showed cytologic features similar to those of the primary abdominal mass, including a prominent desmoplastic reaction of the stroma. Immunocytochemical studies showed myogenic and epithelial differentiation. Molecular analysis was performed on FNA, revealing the EWS/ WT1 chimeric transcript and thus confirming the cytologic diagnosis.
Conclusion: Cytomorphologically, a definitive diagnosis of DSRCT may be difficult, as this tumor bears considerable resemblance to other small round cell tumors. The diagnosis can be confirmed by ancillary techniques, such as immunocytochemistry, and particularly by molecular analysis, which may also be performed on cytologic material.