ABSTRACT
Secondary deep vein thrombosis due to a mass effect on the venous system has been reported in the literature. Venous thrombosis is frequently seen in the lower extremities; however, when seen at the iliac level, the mass effect of an underlying pathology must be considered. Identifying such etiologies guides the management and reduces the risk of recurrences. Case Presentation: In this report, the authors present a case of an extended iliofemoral vein thrombosis caused by a giant retroperitoneal abscess (RA) in a 50-year-old woman with underlying type 2 diabetes mellitus, presenting with painful left leg swelling and fever. Color venous Doppler ultrasonography and computed tomography scan of the abdomen and pelvis findings were compatible with a left voluminous RA compressing the left iliofemoral vein with an extended deep vein thrombosis. Conclusions: The mass effect on the venous system is rare in RAs, but it must be kept in mind. In light of this case and literature review, the authors highlight the diagnosis and management difficulties in handling this unusual presentation form of a RA.