Rhabdomyosarcoma is the most common type of soft-tissue sarcoma, who invade and destroy nearby tissues. Rhabdomyosarcoma has defective myogenic differentiation and the alveolar subtype is the most aggressive, with hithgrade malignancy. We present the case of a 13-years-old girl, with a history of pain, functional impairment, red skin colour and swollen of the left thigh. The investigations have shown thrombosis on the left femoral and iliac vein, thrombosis that resulted from genetic predisposition together with the mechanisme of paraneoplastic thrombosis. The imagistic investigation documented retroperitoneal adenopathic masses encompassing the large vesels, gluteal and perianal mases, solid mass in the pancreatic head and multiple bone nodular lesions. The nonhematopoietic malignancies has masquerading acute leukemia on the bone marrow aspirate with atypical blasts (80% from cells population). The histological examination of the biopsy sample following excision of the left inguinal lymphadenopaty have revealed the final diagnosis: Stage IV alveolar rhabdomyosarcoma, with bone marrow infiltration and multiple metastases (inguinal, pelvic, periaortic, perihepatic), pancreatic and orbital metastases.