Desmoplastic small round-cell tumors are a rare malignant tumor that affects male children and young adults. It frequently presents as a large abdominal mass with widespread peritoneal involvement at diagnosis. We report two cases of desmoplastic small round-cell tumors, with diffuse infiltration in the abdomen and pelvis in two adult caucasian males. The first case-report is a middle-aged man and the second a young adult man with early recurrence and diffuse metastatic lymph nodes. Both tumors have a distinct morphology, a polyphenotypic differentiation and a t(11;22) (p13;q12) translocation. The prognosis remains poor and leads to death in most cases, despite surgical resection, radiotherapy and high-dose chemotherapy.