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Journal of the Anatomical Society of India

Lobe And Segment Anomalies Of the Liver

Author(s): Aktan, Z.A1 Savas, R.2 Pinar, Y.1 Arslan, 3

Vol. 50, No. 1 (2001-01 - 2001-06)

For Reprints, request the first author.

Abstract

Congenital liver abnormalities are rare, to our knowledge. Herein, we review discuss & compare the literature on thissubject with our results. In past the diagnosis of some of these abnormalities was possible only at laparotomy or operation. It is possible now to determine them with CT (computed tomography), & MRI (magnetic resonance imaging).

In this study we determine the liver anomalies in 54 cadavers directly and in 383 patients by using CT.

Key words: Hepatic Lobes, Hapatic Segments

Introduction:

Congenital abnormalities of human liver are rare. A possibility of the presence of the abnormal liver has to be kept in mind when an unexplained abdominal mass is encountered. There are many kinds of described congenital abnormalities of the liver as agenesis of its lobes, absences of its segments, deformed lobes, decrease in size of lobes,lobar atrophy, hypoplastic lobes, transposition of the gall bladder & Riedel's lobe.

For many patients with liver cancer, resection of a primary or metastatic tumor is viable method of treatment. It is very important to know the segmentation of the liver for surgeons. Using the Counaud nomenclature, the liver is divided into eight segments. The caudate lobe alone represents segment I. Segment II is the superior portion of the lateral segment of the left hepatic lobe. Segment III is the inferior portion of the lateral segment of the left hepatic lobe. Segment IV occupies the entire medial segment of the left hepatic lobe. Segment V is the inferior portion of the anterior segment of the right hapatic lobe. Segment VI is the inferior portion of the posterior segment of the right hepatic lobe. Segment VII is the superior portion of the posterior segment of the right hapatic lobe. Segment VIII is the superior portion of anterior segment. (Freeny et al, 1994). During surgery, to know the differentiations of these segments is very important.

In this study liver abnormalities are reported with radiologic findings and in cadavers.

Material and Methods:

Between 1997 and 1999, liver lobe and segment anomalies were determined in 383 patient by using CT and in 54 Cadavers. The patients, 190 men and 193 Women, ranged in age from 32 to 64 years (mean age 49.2 years. There were no hapatic parenchymal abnormality or another hapatic pathology in the cases.

Results:

The results for cadavers are shown in Table I (Fig 1, 2)

Table 1. The results for cadavers (n = 54)

  Number of the livers
and the percentages
Normal 29 (53.70%)
Absence of the left lobe 1 (1.85%)
The fusion of the left lobe and quadrate lobe 8 (14.81%)
The fusion of the right lobe and quadrate lobe 6 (11.11%)
Transverse fissure in the quadrate lobe 2 (3.70%)
Absence of the quadrate lobe 2 (3.70% )
The fusion of the caudate lobe and right lobe with fissure in right lobe 2 (3.70% )
Absence of the caudate lobe 4 (7.41% )

The absence of the caudate lobe represents the absence of segment I.

The CT findings are shown in table 2. The left liver lobe was absent in 1 of 383 cases. In five patients, there was no posterior segment of the right lobe (Fig.3). In three patients, the anterior segment of the right lobe was absent (Fig.4). The right lobe was totally absent in only one patient (Fig.5). In this case there was associated agenesis of the gall bladder and hapatic veins. This patient was 43 years old male.

Table.2 The results in CT findings (n = 383)

Normal 363 (94.78%)
Absence of the left lobe liver 11 (2.87%)
Absence of the posterior segment of the right lobe 5 (1.30%)
Absence of the anterior segment of the left lobe 3 (0.78%)
Absence of the right lobe 1 (0.26%)

Discussion:

Absence of a hepatic lobe is a rare anomaly of liver development. It is usually noted incidentily at autopsy or surgery (Demirici & Diren, 1990; Ozgin & Warchauer, 1992; Radin & Collet; 1992). Absent right and left hapatic lobes are generally asymptomatic (Ozgin & Werchauer, 1992). In our study the right lobe was absent in only one case. The patient was a 48 year-old-man with normal liver function tests. Computed tomography of the abdomen showed a normal left lobe, caudate lobe and quadrate lobe. The liver parenchyma was homogenous in appearance.

Agenesis of the right lobe might be associated with billiary tract disease, portal hypertension, and other congenital anomalies (Kakitsubata & Kakitsubata, 1991). In our series, absence of the left liver lobe was seen in 11 cases of 383 CT and one cadaver liver. In cases of absence of the left liver lobe, the position of the gall bladder is also at the left side of the liver. The hepatic lobe anomaly is not always congenital. Therefore, the diagnosis of this anomaly requires other things such as no evidence of liver dysfunction (Kakitsubata & Nakamura, 1991; Yama moto & Kojoh, 1988).

Congenital agenesis of a liver lobe affects the left lobe more than right liver lobe (Demirci & Diren 1990, Kakitsubata & Kakitsubata, 1991; Radin & Collet; 1987). Between 1870 and 1923 there are reported only six cases with agenesis of the right lobe of the liver at autopsy. Between 1956 and 1987 the number of the cases is just 24. (14 men and ten women) (Radin & Colleti, 1987). Some of these patients had additional anomalies such as partial or complete absence of the right side of the diaphragm, intestinal malrotation, or choledochal cyst but we did not see these anomalies in our cases and cadavers.

In our cases, total absence of the left liver lobe was not determined except one cadaver liver and 11 MRI. Agenesis of the right lobe of the liver occurs slightly more often in men. Our case was also a man. In patients with agenesis of the right lobe of the liver, the right hapatic vein will be absent. (Hsu & Cheng, 1997; Radin & Colleti, 1987).

The anterior and posterior segments of the right lobe are separated by the right hapatic vein (Radin & colleti, 1987). Hapatic venous anatomy and thus lobar and segmental anatomy can be demonstrated by CT (Pagani, 1983) sonography (Sexon & Zeman, 1985) and magnetic resonance imaging (Fishar & Wall 1985). In our study, the anterior segment absence of the right lobe was determined in three patients. Postnecrotic cirrhosis malnutrition, biliary obstruction and veno occulusive disease have been associated with atrophy or hypoplasia of a hepatic lobe or segment but in our case the remainder of the liver had a normal appearance and the liver function tests were normal. We considered a probable development abnormality in the segment anomalies also because of no clinical and biochemical evidence.

Table 3. The incidence of the liver anomalies (single or multiple) in cadavers(%)

Cadaver (n = 54)  
Right lobe anomaly n = 8 (14.81%)
Left lobe anomaly n = 9 (16.66%)
Quadrate lobe anomaly n = 16 (29.63%)
Caudate lobe anomaly n = 6 (11.11%)

The incidence of the lobe anomalies was seen very high in our study especially in the cadavers (table 3). It could be very high in society also but the reason why we do not notice them very often may be that these cases are usually asymptomatic. On the other hand it is especially important to keep in mind these liver anomalies in the correct preoperative diagnosis,because it will be helpful for the surgeon in planning biliary surgery or a portosystemic anastomosis.

References:

  1. Chiba, S; Suzuki, T. (1991): A tongue-like projection of the left lobe in human liver, accompanied with lienorenal venous shunt and intrahepatic arterial anastomosis. Okajimas Folia Anatomica Japonica 68(1): 51-66
  2. Demirci, A; Diren, H. B. (1990): Computed tomography in agenesis of the right lobe of the liver.Acta Radiologica 31 : 105-106.
  3. Freeny, P. C; Stevenson, G. W; Margulis and Burhenne's Alimentary Tract Radiology, Volume Two, Fifth Edition, Missouri 1440-1452 (1994).
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  5. Hsu, K. L,; Cheng, Y. F. (1997): Hypoplastic right hepatic lobe with retrohepatic gall bladder complicated by hapatolithiasis and liver abscess: a case report. Hapato-Gastroenterology 44: 803-807.
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  9. Ozgin, B, Warchauer, D. M; (1992): Absent medial segment of the left hepatic lobe: CT appearance. Journal of Computer Assisted Tomography 16 (4) : 666-668.
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  13. Sexon, C. C; Zeman, R. K. (1985): Correlation of computed tomography, sonography, and gross anatomy of the liver. American Journal of Radiology 141: 711-718.
  14. Yamamoto, S; Kojoh, K; (1988): Computed tomograph of congenital absence of the left lobe of the liver. Journal of Computer assisted Tomography 12 : 206.

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Fig. 1. Absence of the left liver lobe in cadaver

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Fig. 2. A transverse fissure in quadrate lobe.

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Fig. 6. Hypoplasia of the left liver lobe

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Fig. 3. Absence of posterior segment of theright lobe (CT)

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Fig. 4. Absence of anterior segment of the left lobe (CT)

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Fig. 5. Absence of the right liver lobe (CT)

1: Department of Anatomy, 2: Department of Radiology, Ege University, Izmir, 3: Department of Anatomy, Celal Bayar University, Manisa TURKEY

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