Tongue-like elongation of the left lobe of liver

Transcription

1 Page 1 of 5 Anatomy Tongue-like elongation of the left lobe of liver P Baruah, PR Choudhury* Abstract Introduction The liver is the largest gland in our body. Liver normally has a larger right lobe and a smaller left lobe. Though the tongue-like projection of the right lobe of the liver, i.e., Riedel s lobe, is commonly found in literature, the left lobe has very few literature. In foetal life, the left lobe is nearly as large as its right and as the haematopoietic activity of the liver is assumed by the spleen and bone marrow, the left lobe undergoes some degeneration. This paper discusses the tongue-like elongation of the left lobe of the liver. Three livers with tongue-like elongation of the left lobe were found during routine dissections of 20 cadavers in the Department of Anatomy, Gauhati Medical College, Guwahati. On examination, the colour, consistency, and texture of the elongated parts were found to be similar to normal livers and histological examination showed normal liver tissue. There was absence of fibrous tissue, so the elongated parts were not the appendix of the liver. Other parts of the liver were normal. Conclusion This type of elongation of the left lobe of the liver may cause symptoms like pressure, pulling and pain in the epigastrium. Moreover, knowledge of this type of liver anomalies will be helpful for surgeons in planning hepato-biliary surgeries. * Corresponding author prcanatomist@gmail.com Department of Anatomy, Fakhruddin Ali Ahmed Medical College, Barpeta, Assam, India Introduction The liver is one of the most precocious embryonic organs and is the centre of haemopoiesis in the foetus. It develops from an endodermal evagination of the foregut and from the septum transversum mesenchyme. The liver is proportionately large during its development. At three months of gestation, the liver almost fills the abdominal cavity and its left lobe is nearly as large as its right. When haematopoietic activity of the liver is assumed by the spleen and bone marrow, the left lobe undergoes some degeneration and becomes smaller than the right 1. According to Barclay-Smith, The changes which the liver undergoes during growth require elucidation. The small size of the left lobe in the adult as compared with an early condition may be either due to its Figure 1: liver no.1 with elongated left lobe. relatively slow growth or to an actual atrophy of liver substance 2. Anomalies of hepatic morphology, as opposed to anatomical variations, are rare. Nevertheless, knowledge of such anomalies is important since they do not always remain clinically latent. A general review of hepatic anomalies can be divided into two categories, i.e., anomalies due to defective development and anomalies due to excessive development of the liver 3. Riedel s lobe was first recognised as an anatomical variant of the liver 4, consisting of an inferior extension of the right lobe of the liver. Variants of anatomy of the left lobe of the liver are less recognised. Congenital deformities of the liver confined to the left lobe are sufficiently extensive to cause symptoms 5. Bismuth-Couinaud segment II is commonly elongated. In segmental

2 Page 2 of 5 Table 1 of left lobe of abnormal liver no.1 and normal liver venosum up to apex of left lobe From lower end of left lip of groove for ligamentum teres up to apex of left lobe liver No cm 6.7 cm 17.5 cm 14.7 cm From tuber omentale to apex of left lobe 11.2 cm 8.4 cm Sum Mean S.D ±3.790 ±4.215 S.E.M ±2.188 ±2.433 The elongated parts were flattened above downwards. Colour, consistency, and texture of the elongated parts were found to be similar to that of normal livers. Various parameters were recorded with measuring tape and tabulated along with the parameters of the normal livers (Tables 1, 2, 3 and 4). Histological studies showed normal liver tissue in the elongated parts (Figure 4). Other parts of the abnormal livers were normal in appearance. Neighbouring structures of the abnormal livers (e.g. spleen, pancreas etc.) were also found normal during dissection. liver anatomy, centrally located in each of the hepatic segments is a segmental branch of the portal vein and hepatic artery, as well as a segmental bile duct. The solitary distal hepatic veins lie between the individual segments 6,7. In this paper, we discuss a tongue-like elongation of the left lobe of the liver. Case Series Three livers with tongue-like elongation of the left lobes were found after dissection of 20 cadavers in the Department of Anatomy, Gauhati Medical College, Guwahati, during The livers were taken out and preserved under 10% formalin for further study. On gross examination, the colour, consistency, and texture of the elongated parts were studied and various parameters (length, breadth, thickness) were measured (taking arbitrary points) under daylight (Figures 1, 2 and 3). The arbitrary points were taken at the base, middle, apex of the elongated parts, at the tuber omentale, at the upper end of the left lip of the groove for ligamentum venosum, and at the lower end of the left lip of the groove for ligamentum teres hepatis. Fixed planes for divisions of the left and right lobes of the liver were considered, which passed through the falciform ligament anteriorly and superiorly and through the groove for ligamentum venosum and teres hepatis inferiorly. These three livers were also compared with normal livers of similar size, shape, and weight. Tissues of both elongated and normal parts of the left lobes of each of the livers were taken for histological study under a light microscope after routine H&E staining. Figure 2: liver no.2 with elongated left lobe. Discussion The branches of the portal vein and tributaries of the hepatic veins are more numerous before birth, after which they are reduced by fusion or degeneration. The foetal portal vein joins the umbilical vein in a smooth right-hand curve, maintained after birth, with a sharp angle between the portal trunk and its left branch; the left vascular lobe may therefore

3 Page 3 of 5 be at a circulatory disadvantage and unable to keep pace in growth with the right 8. At the left end of the adult left lobe, a fibrous band (fibrous appendix of liver) may appear as an atrophied remnant of the more extensive part of the left lobe found in children 8. But in the present study, the histology of the elongated parts of the left lobes showed the central vein with radiating liver cells and absence of any fibrous element; excluding the possibility of being appendix of the liver. Congenital deformities of the liver confined to the left lobe, sufficiently extensive to cause symptoms, must be instructive, since careful search of the literature discloses the record of one case that, in any way, could be regarded analogous 5. Symptoms in this case were, pressure, pulling, and pain in the epigastrium 5. Congenital changes in the form of an enlargement of the left lobe are greater than what may occur in the right 5. Levi Jay Hammond reported in congenital elongation of the left lobe of the liver, that a girl 16 years of Figure 3: liver no.3 with elongated left lobe. Table 2 of left lobe of abnormal liver no.2 and normal liver venosum up toapex of left lobe From lower end of left lip of groove for ligamentumteres up to apex of left lobe age, for a painless tumorous distention of the epigastrium, which she had noticed for nine years, though she had been suffering from spells of distressing discomfort at times for only about two years. On operation, the left lobe of the liver extended entirely across the lesser curvature into the left hypochondrium, where it was flattened out at the extremity over the spleen. The photograph and coloured plate show the tumorous liver No cm 6.8 cm 24.3 cm 21.2 cm From tuber omentale to apex of left lobe 20.3 cm 7.9 cm Sum Mean S.D ±5.246 ±8.015 S.E.M ±3.029 ±4.628 distention and the exact relation of the tongue-like elongation of the organ at the time of operation. The length of the lobe from the free margin of the liver to its apex was six and one-quarter inches; width, one and three-quarters inches 5. Hammond also mentioned that, There is no doubt but that this is a true case of congenital elongation of the left lobe of the liver. It is further shown by numerous autopsies that when the left lobe is deformed, it is usually folded upon itself and more or less incurved 5. Following splenectomy, the liver can change its position and shape. Migration of the left lobe of the liver into the splenic bed in the left upper quadrant is often seen by surgeons immediately after removal of the spleen 9. In the present study, the spleen is normal in all the three cadavers. The characteristic features of a tongue-like projection of the left lobe of the liver in a female adult, accompanied with a large lienorenal venous shunt and intrahepatic anastomosis of the hepatic arteries, are described, as reported by Chiba, Suzuki, Kasai 10. A computed tomography (CT) scan was performed which confirmed a congenital variant of the left lobe of the liver; the left lobe extending

4 Page 4 of 5 Figure 4: Photomicrogarph of elongated part of left lobe of abnormal liver no.1. Table 3 of left lobe of abnormal liver no.3 and normal liver venosum up toapex of left lobe From lower end of left lip of groove for ligamentumteres up to apex of left lobe Table 4 Weights of three abnormal livers and normal livers Weight of abnormal liver posteriorly and lateral to the spleen, 11 as reported by Dunlop and Evans. liver No.3 Weight of normal liver of similar size Liver No gm gm Liver No gm gm Liver No gm 593 gm 10.5 cm 4.3 cm 16.8 cm 15.3 cm From tuber omentale to apex of left lobe 13 cm 5.4 cm Sum Mean S.D ±3.172 ±6.058 S.E.M ±1.832 ±3.498 According to Haaga et al., common normal variants in liver morphology include horizontal elongation of the lateral segment (Bismuth-Couinaud segment II) of the left hepatic lobe, which can extend into the left upper abdominal quadrant and eventually abut or even wrap around the splenic contour. This anatomic variant is more common in women than in men 12. The embryological basis for smaller size of the left lobe is that the haematopoietic function of the liver diminishes sufficiently in the last two months of pregnancy. This is associated with the progressive reduction of its size which mostly affects the left lobe, as explained by Datta 13. Defective development of the left hepatic lobe can lead to gastric volvulus. Conversely, defective development of the right lobe of liver either remains clinically latent or leads to portal hypertension. The origin of the anomalies of hepatic morphology occurring in the course of organogenesis remains to be elucidated. The use of imaging now allows identification of such anomalies prior to the occurrence of an acute complication 3. Sethi has stated that, there was enlargement of the left hepatic lobe in a hypoplastic right hepatic lobe liver. In the present study, the right lobe was normal in all the three livers 14. The hepatic lobe anomaly is not always congenital. Therefore, the diagnosis of this anomaly requires other things such as no evidence of liver dysfunction 15. So, 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 15. Conclusion Patient with tongue like elongation of left lobe of liver may present asymptomatically or with non-specific abdominal or epigastric pain and may present in adulthood. So in this type of anomalies imaging is recommended for proper diagnosis and management.

5 Page 5 of 5 Table 5 Parameters of elongated part of left lobe of three abnormal livers Length Breadth Thickness of the elongated parts liver no.1 liver no.2 liver no.3 from mid-point of the arbitary base to the apex of elongated part References 1. Standring S. Gray s Anatomy. Pelvic girdle and lower limb, 40th edn. Edinburg, London, New York, Oxford, Philadelphia, St. Louis, Sydney, Toronto: Elsevier Churchill Livingstone, p Barclay-Smith E. A liver exhibiting Multiple Anomalies. J Anat Physiol Jul;43(Pt 4): Champetier J, Yver R, Letoublon C, Vigneau B. A general review of anomalies of hepatic morphology and their clinical implications. Anat Clin. 1985;7(4): Firkin BG, Whitworth JA. Riedel Lobe. Dictionary of Medical Eponyms. London: Parthenon Publishing, Hammond LJ. Congenital Elongation of the Left Lobe of the Liver. Ann Surg Jan;41(1): Haaga JR, Dogra VS, Forsting M, Gilkeson 5th edn. Vol. 2. Philadelphia: Mosby Elsevier; p Haaga JR, Dogra VS, Forsting M, Gilkeson 5th Edn. Vol.2. Philadelphia: Mosby Elsevier; p Williams PL, Bannister LH, Berry MM, Collins P, Dyson M, Dussek JE, Ferguson MWJ. Gray s Anatomy. In Alimentary system, 38th edn. Edinburgh, London, Newyork, Philadelphia, Sydney, Toronto: Churchill Livingston; p Custer JR, Shafer RB. Changes in liver scan following splenectomy. J Nucl Med Mar;16(3): Chiba S, Suzuki T, Kasai T. A tongue-like projection of the left lobe in human liver, accompanied with lienorenal venous shunt and intrahepatic arterial anastomosis. 6.3 cm 13.8 cm 8.2 cm at the base 5.4 cm 7.5 cm 7 cm at the middle 5 cm 6.8 cm 6.5 cm near the apex 3.2 cm 5.2 cm 4.3 cm at the base 0.6 cm 1.2 cm 0.8 cm at the middle 1 cm 1 cm 1 cm near the apex 0.4 cm 0.5 cm 0.4 cm Sum Mean S.D ±2.486 ±4.787 ±3.296 S.E.M ±0.939 ±1.809 ±1.246 Okajimas Folia anat Jpn May; 68(1): Dunlop DG, Evans RM. Congenital abnormality of the liver initially misdiagnosed as splenic haematoma. J R Soc Med Dec;89(12): Haaga JR, Dogra VS, Forsting M, Gilkeson 5th Edn. Vol.2. Philadelphia: Mosby Elsevier; p Datta AK. Essentials of human embryology in the alimentary system. 6th edn. Kolkata, India: Current Books International, p Sethi SK, Solanki RS. A case report hypoplastic right hepatic lobe a rare anomaly. Abdomin Imag. 2004;14(1): Aktan ZA, Savas R, Pinar Y, Arslan O. Lobe and segment anomalies of the liver. J Anat Soc India Jan;50(1):15 16.