A 13-year-old female patient was admitted to our hospital for the first time on June 12, 2010 due to bruises on the right waist for more than 20 days, gross hematuria, and fever for half a month. Figure 1 is a timeline of the patient's clinical course and treatments. The right side of the patient's waist hit a hard object, resulting in lumbago on May 15, 2010. One week later, she began to develop gross hematuria, visible blood clots, no frequent and urgent urination, and no dysuria, with fever and a maximum body temperature of 38  C. She gradually developed nausea, vomiting, and edema of both lower extremities. Physical examination revealed normal blood pressure, normal development, pale complexion, clear consciousness, no jaundice, and no palpable enlargement of superficial lymph nodes. There was no congestion in the pharynx and no swelling of the tonsils. Cardiopulmonary examination showed no abnormalities. The abdomen was flat and soft, no abdominal mass was palpated, the liver was impalpable below the costal margin, there was no percussion pain in the bilateral kidney area, and no tenderness and rebound tenderness in the bilateral ureteral area. Pitting edema occurred in both lower limbs, muscle strength and muscle tone of the limbs were normal, and physiological reflexes were present. Color doppler ultrasound showed hypoechoic masses in the wall of the inferior vena cava (Figure 2A), and of the right renal vein (Figure 2B), considering the possibility of thrombosis. White blood cell count (WBC) was 17.7 x 109/L, hemoglobin was 103 g/L, neutrophil ratio was 76.70%, and platelet count was 159 x 109/L, all normal values of specific detection indexes were showed in Table 1. Albumin 26.7 g/L, blood urea nitrogen (BUN) 10.50 mmol/L, and creatinine 189.5 mumol/L were tested. Coagulation testing showed prothrombin time (PT) 10.6 s, activated partial thromboplastin time (APTT) 31.7 s, and D-dimer quantitative level 33.67 mug/ml. Microscopic examination of erythrocyte 3+/HP was found in urine and 24 hour urinary protein quantity was 5.0 g/L. After hospitalization, albumin supplementation and cefmenoxime anti-infection treatment were given. The day after admission, she suddenly experienced severe chest pain and shortness of breath, which lasted for about 10 s and then improved. The subsequent physical examination showed blood pressure 120-145/75-90 mmHg, transcutaneous oxygen saturation 80%, clear breath sounds in the left lung, decreased breath sounds in the right lower lung, and no dry/wet rales heard. The patient had persistent fever, bad psychosis, and occasional headache. Pulmonary artery CT angiography (CTA) showed embolisms of the distal main pulmonary artery, left pulmonary artery trunk and its intrapulmonary branches, and the right lower pulmonary artery (Figure 2C), as well as exudation and consolidation of bilateral lower lobes, considering the possibility of ischemic infarction. Brain MRI showed normal. Cholesterol was 6.75 mmol/L, 24 hour urinary protein quantity was 1.1 g, albumin was 13.7 g/L, erythrocyte sedimentation rate (ESR) was 97 mm/h and C-reactive protein (CRP) was 5.25 mg/L. Immunoglobulin IgG was 5.67 g/L, there were normal complement C3 and C4 (1.04 g/L and 0.13 g/L respectively), and all negative results for vasculitis, anticardiolipin antibody, anti-ANA, anti-dsDNA, anti-Sm antibodies and extractable Nuclear Antigen (ENA). She was immediately given low molecular heparin and urokinase for thrombolysis. The inferior vena cava filter was implanted under digital substraction angiography (DSA) on June 17, 2010. The patient was diagnosed with NS and thrombogenesis. Due to the use of anticoagulants, the patient was concerned about the risk of bleeding and the kidney biopsy was not completed. Then the patient took cefmenoxime for anti-infection and drugs for anticoagulation and thrombolysis, adding low-dose methylprednisolone for suppressive immunotherapy. However, the patient continued to have hypoalbuminemia and massive proteinuria, BUN and creatinine were at a high level persistently. The inferior vena cava filter was removed under local anesthesia, and cyclophosphamide pulse therapy was added 20 days later. On July 20, she was switched to warfarin for anticoagulation. The edema basically subsided, and the proteinuria gradually decreased. After discharge, the patient underwent regular follow-up checkups, the thrombi disappeared (Figure 2D). Then her urine protein turned negative after half a year, and she continued to take oral prednisone and mycophenolate mofetil (MMF) for immunosuppression, antihypertensive metoprolol, and anticoagulative warfarin for 1 year. As multiple urine analysis tested normal, all drugs were gradually reduced to stop on February 22, 2012. On July 18, 2015, the patient had no obvious cause for non-pitting edema of both eyelids and lower extremities, visible retiform purpura, and a little rash on the back of the feet. Laboratory inspections showed complement C3 < 0.179 g/L, complement C4 < 0.0643 g/L, CRP 0.72 mg/L, negative anticardiolipin IgA and anti-beta2GP1 antibody, while anticardiolipin IgG and IgM, lactic acid (LAC), anti-Anti-nuclear antibody (ANA) (1:160), ds-DNA, anti-neutrophil cytoplasmic antibodies (ANCA), anti-U1-nPNP (3+), anti-Sm (3+), anti-centromere (3+), anti-dsDNA (2+), anti-nucleosome (+), and anti-ribosomal P protein (3+) antibodies were all positive. Moreover, lymphocyte subsets, direct antiglobulin test (DAT), tuberculosis (TB) and hepatitis B tests were all negative. BUN was 7.23 mmol/L, creatinine was 80.0 mumol/L and 24 h urinary protein was 1.0 g/L. Renal pathology suggested lupus nephritis (LN) (type VI according to ISN/RPS Classification Standard) (Figures 3A-I). The patient was given ceftazidime for anti-infection, oral hydroxychloroquine, fosinopril for kidney protection, heparin sodium, urokinase for anticoagulation and thrombolysis, and dipyridamole for antiplatelet aggregation, followed by 5-time cyclophosphamide pulse therapy, then she was treated with oral MMF, and high-dose methylprednisolone for 3 days before oral prednisone. The patient underwent 3-time allogeneic cord blood stem cell infusions and was discharged from the hospital after her condition improved. The patient took medicine regularly post-discharge. The edema of both lower extremities and eyelids progressively worsened, and the knee joints were painful on November 28, 2015. Serum complement C3 was 0.84 g/L and C4 was normal. Jo-1 (+), Scl-70 (+), anti-ANA (homogeneous type) and anti-C1q (+) antibodies and LAC were all positive, anticardiolipin antibody was negative. Vascular B-ultrasound showed bilateral popliteal vein blood flow, and bilateral mural thrombosis was considered (Figures 1E,F). The patient was treated with rituximab for immunosuppressive therapy, cefotiam for anti-infection, heparin sodium, urokinase for anticoagulation and thrombolysis, sequential warfarin and dipyridamole for anticoagulation, and continued oral prednisone, MMF, and hydroxychloroquine. After discharge, the patient was regularly followed up, and the urine protein gradually turned negative, and then all the drugs were gradually stopped. Currently, she has been off medication for 5 years and is generally in good condition.