Para-aortic lymphoma simulating mycotic abdominal aortic aneurysm.

A 70-year-old man presented with 6 months' history of progressively severe backache and left frank pain. Past history was significant for an aortobifemoral Dacron bypass graft performed 11 years ago for intermittent claudication attributable to aortoiliac occlusive disease. A contrast computed tomogra-phy (CT) scan showed a slight irregularity around the pararenal aorta without other abnormalities. Because of persistent symptoms , a positive emission tomography-CT scan was performed that showed a large pseudoaneurysm measuring 6.1×3.8×2.8 cm arising from the juxtarenal aorta above the previous aortic graft (Figure 1) with an associated retroperitoneal soft tissue mass encasing the left renal artery with a standardized uptake value of 22.5 (Figure 2). At this stage, the differential diagnosis was of juxtarenal aortic mycotic aneurysm or an anastomotic pseudoaneurysm with contained rupture, or retroperitoneal tumor with aortic invasion. The patient was referred to our ter-tiary vascular center for further management. On admission, the patient was frail. The blood test revealed pancytopenia (white blood cells, 4.0×10 9 /L; hemoglobin, 10.2 g/ dL; platelets, 131×10 9 /L) and raised lactate dehydrogenase of 861 U/L (normal range, 118–221 U/L). C-reactive protein and erythrocyte sedimentation rate were also increased to 9.11 mg/dL (normal range, <0.76 mg/dL) and 117 mm/h (normal range, 0–10 mm/h), respectively. Repeated blood cultures were negative. Because the patient was symptomatic and deemed unfit for open repair, with the inherent risk of contained rupture, we decided to temporalize the condition with parental ceftriaxone and repaired the pseudoaneurysm in the endovascular approach. A bifurcated device (Endurant ENBF 28-13C-120; ENLW 16-13C-95; Medtronic, MN) was chosen in view of the short distance between the renal arteries and the previous graft. The stent graft was positioned above the previous prosthetic aortic graft, reaching the renal arteries at the top and landed on both aortic graft limbs (Figure 3). The patient's condition remained unimproved post-operatively. The retroperitoneal mass persisted despite successful exclusion of the aorta pseudoaneurysm and antibiotics (Figure 4). Diagnosis of retroperitoneal tumor was more likely at this stage. Hence, a CT-guided Tru-Cut biopsy of the retroperitoneal mass was performed. It revealed foci of viable perivascular tumor cells with nuclei pleomorphism. Immunohistochemistry staining showed the expression of B-cell marker CD20 and BCL2. The Ki-67 index was 70%. The features were consistent with diffuse large B-cell lymphoma (Figure 5). Chemotherapy with the use of the IMVP-16 regi-men (ifosfamide, methotrexate, etoposide) was commenced. The patient eventually died 1 year after the aortic …