Desmoplastic Small Round Cell Tumor : Differential Diagnosis
The differential diagnosis of desmoplastic small round cell tumor (DSRCT) is wide and includes other small round blue cell tumors such as Ewing family of tumors, alveolar rhabdomyosarcoma, neuroblastoma, lymphoma, poorly differentiated carcinoma, small cell carcinoma, Merkel cell carcinoma, and malignant mesothelioma. The coexpression of epithelial, mesenchymal, and neural markers, especially the paranuclear/globular dot-like positivity for desmin is quite helpful. In difficult or atypical cases, RT-PCR or FISH analysis for EWSR1-WT1 fusion can be performed. The image shows cords of undifferentiated tumor cells arranged concentrically around blood vessels in a background of desmoplastic stroma from a case of DSRCT.