ANATOMICAL VIGNETTE

Right Posterior-Superior SubsegmentalHepatic Artery Originating from the RightInferior Adrenal ArterySatoshi Kobayashi, Osamu Matsui, Masumi Kadoya, Toshifumi Gabata,Junichirou Sanada, Noboru Terayama

Department of Radiology, Kanazawa University School of Medicine, 13-1, Takara-machi, Kanazawa, 920-8641, Japan

Many anatomic variants of the hepatic artery have beenreported [1–5]. Hiatt et al. [5] studied hepatic arterial pat-terns in 1000 cases of donor livers, and classified them intosix patterns. The hepatic arteries originated from the com-mon hepatic artery in 75%; however, about 22% had areplaced or accessory hepatic artery. Michels et al. [6] di-vided aberrant arteries into two categories: an “accessory”artery and a “replaced” artery. The replaced right hepaticartery is seen primarily to branch from the superior mesen-teric artery (SMA), with the incidence of this anomaly beingabout 17% [1]. Total replacement of the right hepatic arteryoccurs in about 12%, and partial replacement in about 5%[1].

Recently, during CT arteriography we encountered a caseof a replaced right superior subsegmental artery originatingfrom the right inferior adrenal artery, which was confirmedby conventional arteriography. To our knowledge, this typeof hepatic arterial anomaly is very rare and has not beenreported previously.

Case PresentationA 76-year-old woman was admitted to our hospital to rule outhepatocellular carcinoma (HCC). The patient had hepatitis C andcirrhosis. On ultrasonography and magnetic resonance imaging(MRI), a small tumor was noted in segment VIII of the liver. Forcloser examination of this tumor, conventional hepatic arteriogra-phy (CHA), CT during hepatic arteriography (CTHA), and CTduring arterial portography (CTAP) were performed, and a smallhypovascular tumor was observed in segment VIII of the liver byCTHA. Needle biopsy was performed following the imagingworkup, and histopathology showed adenomatous hyperplasia(AH) of the liver. Moreover, a subsegmental non-tumoral perfusiondefect was observed in segment VII of the liver on CTHA (Fig. 1).However, the area showed no portal perfusion defect on CTAP

(Fig. 2). In this case, the catheter tip was placed in the commonhepatic artery at CTHA to perform a common hepatic CHA wherethe posterior superior subsegmental artery was not opacified (Fig.3). These findings indicated the presence of an aberrant hepaticartery branch to segment VII originating from somewhere otherthan the common hepatic artery. We searched for the origin of thissubsegmental hepatic artery, and on right renal arteriography, asmall arterial branch running toward the right lobe of the liver wasobserved originating from the proximal right inferior adrenal artery(Fig. 4). We inserted a microcatheter into the right inferior adrenalartery, performed CT during right inferior adrenal arteriography,and confirmed that the arterial branch was supplying segment VIIof the liver, where the perfusion defect was observed on the CTHA(Fig. 5). Because there was no other arterial branch which supplied

Correspondence to: S. Kobayashi, M.D.; e-mail: satoshik@med.kanazawa-u.ac.jp

Fig. 1. On CT during hepatic arteriography performed fromthe common hepatic artery, a subsegmental perfusion defectin segment VII of the liver was observed (arrows).

CardioVascularand InterventionalRadiology

© Springer-Verlag New York, Inc. 2001 Cardiovasc Intervent Radiol (2001) 24:271–273Published Online: 19 June 2001 DOI: 10.1007/s00270-001-0021-y

segment VII of the liver, we determined that this arterial branch wasa replaced right posterior superior subsegmental artery supplyingsegment VII of the liver. Moreover, on CTAP, a posterior-superiorportal branch (segment VII) accompanied this artery from thehepatic hilus where both the artery and the portal vein penetratedinto the liver (Fig. 2).

CommentsA number of reports have been published on anatomic vari-ations of the hepatic arteries [1–5], some variations are

Fig. 2. On CT during arterial portography, no decrease inportal perfusion in segment VII was seen. The portal venousbranch of segment VII of the liver is running along the lowerportion of right hepatic hilus (arrow), and enters the liver,where the replaced right posterior-superior subsegmentalartery originating from the right inferior adrenal artery alsopenetrates into the liver (see also Fig. 5).

Fig. 3. On late arterial phase of a selective common hepaticarteriogram, the right posterior superior sub-segmental arterywas not opacified.

Fig. 4. Early arterial phase of a selective right renal angio-gram demonstrates a replaced right posterior superior sub-segmental artery arising from the inferior right adrenal arterywhich branches at the proximal part of the right renal artery(arrows). Right inferior phrenic artery also branches fromthere (arrowheads).

Fig. 5. Staining of Segment VII was demonstrated by CTduring right inferior adrenal arteriography. Comparing thisfigure with Figure 2, we see that the arterial branch accom-panies the portal venous branch at the point that the arterypenetrates into the liver (arrow).

272 S. Kobayashi et al.: Replaced Right Hepatic Artery from Inferior Adrenal Artery

relatively common. However, a replaced hepatic artery orig-inating from the right inferior adrenal artery must be con-sidered rare. Only one case similar to ours was reported byBraun et al. [7], an aberrant right hepatic artery arising fromthe renal artery. The difference between these two cases isthat in Braun’s case, the entire right hepatic arterial systemarose from the right renal artery [7], whereas in our case, thereplaced hepatic artery supplied only a subsegment of theright lobe of the liver. The rest of the liver was supplied bythe proper hepatic artery.

Braun et al. [7] hypothesized that the aberrant origindeveloped from the 11th or 12th vitelline branch when thecaudally migrating right hepatic artery fused with the ros-tally migrating right renal artery to form a common aorticbranch [7]. We assume that our case represents a similardevelopmental anomaly.

Our case also raises the question as to whether the ob-served artery represents a replaced hepatic artery or a col-lateral artery. Since hepatic segment VII is located adjacentto the right adrenal gland, one could assume that the arterialbranch is a collateral vessel from the inferior adrenal arteryvia the hepatic capsular artery to the hepatic parenchyma ofsegment VII. However, our patient had no previous historyof therapeutic embolization or surgery which might have

triggered development of a collateral supply. In addition, thereplaced artery was accompanied by a portal venous branchthat would not be expected for a collateral artery. Thereforethis vessel cannot be considered a collateral but a replacedartery. Knowledge of this rare anatomic variant of the he-patic artery is helpful for the diagnostic work-up of patientssuch as the one presented, as well as for transarterial embo-lization and surgery.

References1. Michels NA (1966) Newer anatomy of the liver and its variant blood

supply and collateral circulation. Am J Surgery 112:337–3472. Suzuki T, Nakayasu A, Kawabe K, Takeda H, Honjo I (1971) Surgical

significance of anatomic variations of hepatic artery. Am J Surgery122:505–512

3. Charnsangavej C, Chuang VP, Wallace S, Soo CS, Bowers T (1982)Angiographic classification of hepatic arterial collaterals. Radiology144:485–494

4. Rygaard H, Forrest M, Mygind T, Baden H (1986) Anatomic variants ofthe hepatic arteries. Acta Radiol Diagn 27:425–427

5. Hiatt JR, Gabbay J, Busuttil RW (1994) Surgical anatomy of the hepaticarteries in 1000 cases. Ann Surg 220:50–52

6. Michels NA (1955) Blood Supply of Upper Abdominal Organs. Lippin-cott, Philadelphia, pp 134–195

7. Braun MA, Collins B, Wright P (1991) An aberrant right hepatic arteryfrom the right renal artery: Anatomical vignette. Cardiovasc InterventRadiol 14:349–351

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