This is “Advance Publication Article” Kurume Medical Journal, 64, 103-107, 2017 Case Report A Retroaortic Left Renal Vein in a Female Cadaver YOSHIKO FUJISHIMA, KOICHI WATANABE*, YOKO TABIRA*, JOE IWANAGA*,**, †, YUI ODO, TSUYOSHI SAGA*, R. SHANE TUBBS**, ‡ AND KOH-ICHI YAMAKI* Medical student, Kurume University School of Medicine, *Department of Anatomy, Kurume University School of Medicine, Kurume, 830-0011 Japan, **Seattle Science Foundation, Seattle, 98122 United States, †Dental and Oral Medical Center, Kurume University School of Medicine, Kurume 830-0011, Japan, ‡Department of Anatomical Sciences, St. George’s University, St. George’s, Grenada. Received 4 October 2017, accepted 23 November 2017 J-STAGE advance publication 21 May 2018 Edited by TOSHI ABE Summary: We encountered a case of retroaortic left renal vein (RLRV) during an anatomical dissection course at our medical school in 2017. The case was a female cadaver who was 88 years old at death. Six roots of the left renal vein (RV) arose from the hilus of the kidney and joined to form one left renal vein, crossed dorsal to the abdominal aorta (AA) at the level of the second lumbar vertebra, and then drained into the inferior vena cava (IVC). Two roots joined at the right renal hilus to become the right RV to then drain into the IVC at the level of the first lumbar vertebral body. The reported frequency of RLRV is approximately 2%. Embryologically, the normal anastomosis of the left and right sub-cardinal veins results in the left RV traveling on the ventral surface of the AA. However, in the case presented here, the left RV traveled on the dorsal side of the AA due to the anastomosis of the left and right supra-cardinal veins and regression of the anastomosis between the left and right sub-cardinal veins. If both the dorsal and ventral anastomoses remain, the left RV travels on the dorsal and ventral sides of the aorta. Some of the clinical problems reported in association with RLRV are hematuria and abdominal pain, and the risk of damaging the RLRV during surgery of the posterior abdominal wall. Venous vari- ants as reported herein should be kept in mind when interpreting imaging of the posterior abdominal wall or per- forming surgery or other invasive procedures near the RLRV. Key words retroaortic left renal vein, inferior vena cava, kidney, renal artery, cadaver, dissection, anatomy INTRODUCTION CASE REPORT A retroaortic left renal vein (RLRV) was found dur- The RLRV was found in a female Japanese ca- ing routine anatomical dissection. This variation occurs daver whose age at death was 88 years old. (Figure 1, in approximately 2% of the population. Clinically, the 2) The cause of death was cancer of an unknown pri- nutcracker phenomenon, caused by narrowing of the mary origin. There were no scars around the skin of left RV between the descending aorta and the spinal the abdomen. column, places this vessel at risk during abdominal aortic surgery. Therefore, awareness of this variation Inferior vena cava (IVC) has clinical and surgical significance. The right and left common iliac veins joined at the position of the fourth lumbar vertebral body to become Corresponding Author: Joe Iwanaga DDS, Ph.D, Department of Anatomy, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830- 0011, Japan. Tel: +81-942-31-7540, Fax: +81-942-33-3233, E-mail: [email protected] Abbreviations: AA, abdominal aorta; IVC, inferior vena cava; RLRV, retroaortic left renal vein; RV, renal vein 104 FUJISHIMA ET AL. Fig. 1. The abdominal cavity Arterial system; A superior mesenteric artery, a right renal artery, two left renal arteries, inferior mesenteric artery and right and left common iliac artery arising Fig. 2. Arteries, veins, kidney and adrenal gland from the descending abdominal aorta. removed from abdominal cavity. Venous system; Right and left common iliac vein join- Arterial system; Abdominal aorta branching superior ing to become inferior vena cava and right ovarian mesenteric artery, inferior mesenteric artery, right and vein, right and left renal vein, and hepatic vein flow- left common iliac arteries. ing into inferior vena cava. Venous system; Right renal vein flowing into inferior AA, abdominal aorta; AG, adrenal gland; CIA, com- vena cava and left renal vein running transversely mon iliac artery; CIV, common iliac vein; IMA, infe- behind abdominal aorta and flowing into inferior vena rior mesenteric artery; IVC, inferior vena cava; K, kid- cava. ney; LRA, left renal artery; RRV, right renal veins; AA, abdominal aorta; AG, adrenal gland; CIA, com- SMA, superior mesenteric artery; SRA, suprarenal mon iliac artery; IMA, inferior mesenteric artery; IVC, artery; U, ureter. inferior vena cava; K, kidney; RRV, right renal veins; SMA, superior mesenteric artery; SRV, suprarenal vein; U, ureter. the IVC. The fourth and third lumbar veins drained into the IVC posteriorly at the level of the fourth lum- bar vertebral body where the left and right common was at the level of the inferior border of the twelfth iliac veins joined, and at the level of the third lumbar thoracic vertebra, with a length of 105.2 mm and width vertebral body, respectively. The left RV and the right of 36.7 mm. The position of the upper border of the ovarian vein fl owed into the IVC at the level of the right kidney was at the level of the superior border of second lumbar vertebral body, the right adrenal vein the twelfth thoracic vertebra, with a length of 106.45 fl owed into the IVC at the level of the fi rst lumbar mm and width of 40.7 mm. Although the right kidney vertebral body, and the hepatic veins drained into the was slightly larger than the left, no abnormality was IVC at the vena caval foramen. seen in regard to shape or size. Morphology of the kidney Left renal vein The position of the upper border of the left kidney Six roots of the left RV arose from the hilus and Kurume Medical Journal Vol. 64, No. 4 2017 RETROAORTIC LEFT RENAL VEIN 105 joined into one left renal, received the left ovarian vein vein and merged with the IVC at the level of the fi rst (4.2 mm in diameter) and the left suprarenal vein (4.4 lumbar vertebral body. The width of the right RV at the mm in diameter), crossed dorsal to the abdominal aorta junction of the two roots was 13.60 mm and the length (AA) slightly downward at the level of the second of the right RV from the right renal hilus to the point lumbar vertebra, and then drained into the IVC. The where the right RV drained into the IVC was 18.20 mm. left RV dorsal to the AA received the fi rst lumbar vein from the upper wall, and the ascending lumbar vein and Left renal artery the second lumbar vein from the lower wall. (Figure Two left renal arteries were observed, the upper and 3) At the upper wall of the left RV where it drained into lower renal arteries. The upper one arose from the AA the IVC, a small branch ascended behind the AA to just below the origin of the superior mesentery artery become the hemiazygos vein. The diameter of the left and drained into the renal parenchyma, which was RV was 9.00 mm where the six roots joined to become above the renal hilus. The lower one originated from the single left RV with a maximum of 21.00 mm and a the AA at the level of the second lumbar vertebra, minimum of 14.80 mm posterior to the abdominal coursed behind the right suprarenal vein and drained aorta. Total length of the left renal vein was 75.20 mm, into the renal hilus. with a part 23.30 mm in length behind the AA. Right renal artery Right renal vein The right renal artery arose from the AA at the same Two roots joined at the right renal hilus to become level as the upper left renal artery and traveled upward the right RV, which received the right inferior phrenic toward the renal hilus. Fig. 3. Posterior view of Figure 2. Artery The descending abdominal aorta giving rise to the middle suprarenal artery, left renal artery, and right renal artery. The first, second, third lumbar arteries branching from the posterior aspect of the abdominal aorta. Vein The right renal vein draining from the right kidney and passing behind the descending abdominal aorta and then draining into the inferior vena cava. The first, second, and third lumbar veins flow into the infe- rior vena cava at the same level as each lumbar artery. AA, abdominal aorta; AG, adrenal gland; G, left ovarian vein; IVC, inferior vena cava; K, kidney; LRA, left renal artery; L1, the first lumber vein; L2, the second lumber vein; L3, the third lumber vein; MSA, middle suprarenal artery; RLRV, retroaortic left renal vein; RRA, right renal artery. Kurume Medical Journal Vol. 64, No. 4 2017 106 FUJISHIMA ET AL. kidneys, the left and right supracardinal veins form an DISCUSSION anastomosis between the azygos and hemiazygos veins. The RV is normally a large vein and runs trans- In the area around the kidney, the supracardinal-sub- versely in front of the renal artery. The left RV is longer cardinal veins anastomose and the left and right supra- than the right RV and runs just inferior to the origin of cardinal venous anastomosis is formed. Caudal to the the superior mesenteric artery anterior to the AA. The kidney, the left subcardinal vein disappears and the left testicular (or ovarian), left inferior phrenic, and right subcardinal vein becomes part of the IVC [8].