A 8-years-old girl visited clinic because of intermittent gross hematuria for 3 days. At physical examination revealed no specific abnormal findings. She had no personal history of renal diseaes, pulmonary tuberculosis and drug abuse. Laboratoty data : (1) CBC : Hb 12.8 gm%, WBC 4,400 /cmm, platelet 276 K/uL (2) U/A : colorless, PH 6.0, SG 1.025, glucose (-), protein (-), blood (-), ketone (-), bilirubin (-), nitrite (-), RBC 0-1 / HPF, WBC 0-1 / HPF (3) BUN 11.7 mg/dL, glucose 121 mg/dL, total cholesterol 156 mg/dL, total protein 7 g/dL, albumin 4.5 g/dL, total bilirubin 0.5 mg/dL, ALP 1,001 U/L, LDH 403 U/L, ALT 20 U/L, AST 28 U/L, serum Na 145 mEq/L, K 4.3 mEq/L, Cl 108 mEq/L (4) prothrombin time 11.3 sec 97.8 %, aPTT 30.7 sec (5) ferritin and alpha-FP : normal, bone marrow aspiration : normal (6) bone scan (MIBG) : increased uptake (7) Urine VMA 2 mg/day. Abdomen ultrasonogram reveals huge homogenous echoic round mass (4.4 x 5.2 x 6.4 cm) in subhepatic region which is growing or attached to liver. There is noted ovoid mass in right adrenal gland. There are also noted multiple lymph nodes enlargement in retrocaval and pericaval region. GB and biliary tracts appear unremarkable. Both kidneys, spleen and pancreas appear unremarkable. Impression : Huge mass in subhepatic region with right adrenal gland metastasis and multiple metastatic lymph adenopathy in retrocaval and pericaval region. -> Hepatoblastoma is suggested. On Abdomen CT reveals huge relatively homogenous round mass within liver. After contrast media injection, there was a marked inhomogenous enhancement of mass within liver with interior growing which size is 4.7 x 6.4 cm in dimension. There shows displacement of portal vein and IVC due to compression by mass. There shows multiple masses in pericaval region and right adrenal gland mass. Pancreas and both kidneys appear unremarkable. Pelvic organs appear unremarkable. Impression ; Hepatoblastoma with metastasis to right adrenal gland and multiple metastatic lymph nodes in pericaval region. The patient underwent laparatomy under general anesthesia. An ill defined huge retroperitoneal mass was noted and located at portal triad area. IVC, portal rein and CBD were adhesed with mass. An incisional biopsy of main mass was done and perigastric lymph nodes was excised. Gross findings ; The submitted specimen consists of three groups. The first specimen consists of pinkish gray polypoid tissue, measuring 1.8 x 1.4 cm in dimension. The cut surface shows whitish pink solid appearance. The second specimen labeled as 8p lymph node consists of a piece of tissue. The third specimen labeled as 13th lymph node. Microscopic findings : The retroperitoneal mass shows scattered or grouped abnormal ganglion cells and proliferation of schwann cells. Diagnosis ; I. Retroperitoneum, supra adrenal, right, incisional biopsy ; Ganglioneuroma II. Lymph node, frozen biopsy. 1. 8p ; No tumor metastasis (0/1) 2. 13th ; No tumor metastasis (0/1). ① IlBong Kim, ② KiMan Lee, ③ HongJin Kim, ④ DongSug Kim*** ① Dr. Kim ilbong Internal Medicine Clinic, Taegu, Korea, ② DaeKyung Radiology Clinic, Taegu, Korea ③ Department of Surgery, College of Medicine, Yeungnam Univ., ④ Department of Pathology, College of Medicine, Yeungnam Univ. Retroperitoneal Ganglioneuroma Fig4.,Fig5.,Fig6. Ultrasonogram Fig1.,Fig2.,Fig3. Ultrasonogram Fig7, Abdomen CT Fig8, Abdomen CT Fig9, Abdomen CT Fig10, Fig11, Fig12 Abdomen CT, Fig13, Abdomen CT Fig14, Abdomen CT Fig15, Abdomen CT Fig16, Gross Findings ◆육안소견 : The cut surface of the retroperitoneal mass is solid and yellow tan. ◆현미경소견 : The retroperitoneal mass shows scattered or grouped abnormal ganglion cells and proliferation of schwann cells.