Desmoid tumor is a rare neoplasm with extra-abdominal location and female predilection. Anatomopatological analysis is necessary to establish the diagnosis unequivocally, but Magnetic Resonance is the no aggressive method with the best sensitivity and specificity. Surgical resection is the elective treatment yet, and prognosis is not so good as it could be expected in a benign tumor. We report a young male case without polyposis coli antecedents. When he was attended, he related only an abdominal bulk with no other symptom. An intra-abdominal mass 32 cm length per 25 cm width consistent with desmoid tumor was finally resected.