Fig. 1Abdominal computerized tomography (CT) scan at diagnosis revealed well-enhanced abdominal masses encircling the 1st and 2nd portion of duodenum (A) and multiple intrahepatic masses (B).
Fig. 2Esophagogastroduodenoscopy revealed a huge protruding ulceroinfiltrative mass in the 2nd portion of duodenum. Further advance of endoscopy beyond this point was impossible due to the mass.
Fig. 3Microscopic findings of duodenoscopic biopsy specimen are as follows: H & E stain (×800) revealed poor differentiation (A) and CD99 (×800) was positive in membranous pattern (B).
Fig. 4Molecular genetic methods were helpful for diagnosis of desmoplastic small round cell tumor. The result of FISH for EWS gene translocation with EWSR1 break apart probe was positive (A) and the result of EWS/Fli1 rearrangement RT-PCR, which is sensitive to Ewing sarcoma/PNET, was negative (B).