Eur J Cardiothorac Surg 2002;21:558-560
© 2002 Elsevier Science NL
Left-sided congenital diaphragmatic hernia associated with intrathoracic ectopic liver lobule
A. Bedii Salman*
Department of Pediatric Surgery, Atatürk University Medical Faculty, 25240 Erzurum, Turkey
Received 14 September 2001;
received in revised form 27 November 2001;
accepted 4 December 2001.
* Tel.: +90-442-2360660; fax: +90-442-2186782
e-mail: abediisalman{at}hotmail.com
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Abstract
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A case of intrathoracic ectopia of the left lobe lateral segment of the liver in a patient with left-sided diaphragmatic hernia is described. The ectopic liver part was found in the left hemithorax during excision of the diaphragmatic hernia sac, but it was not the content of the sac. The ectopic liver part has not been described previously in the left hemithorax and is actually the primary abnormality. The diaphragmatic hernia is merely a secondary development through this potential gap on the diaphragm where the pedicle of the ectopic liver lobule passes.
Key Words: Ectopic liver • Intrathoracic liver • Diaphragmatic hernia
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1. Introduction
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Ectopic liver tissue has been found separately from the liver in a wide variety of locations, including hepatic ligament, adrenal glands, gallbladder, umbilicus, pancreas, esophagus, thorax, omphalocele, retroperitoneum and splenic capsule as well as in the lesser and greater omentum and elsewhere on the surface of the peritoneum [1,2]. However, ectopic liver is connected with the main liver by a pedicle of hepatic parenchyma or a mesenteric pedicle containing hepatic artery, hepatic and portal veins and bile ducts in order to function, and it has been reported in the abdomen, thoracic cavity, anterior abdominal wall and omphalocele [1–9]. When the ectopic liver is found outside the abdominal cavity, it most often forms part of the contents of an omphalocele or diaphragmatic hernia [1]. In literature, ectopic liver is mentioned as a rare finding and fewer than ten cases of intrathoracic ectopic liver have been reported [3].
Herein, we describe intrathoracic ectopia of the left lobe lateral segment of the liver with left-sided diaphragmatic hernia. It is of particular interest that the intrathoracic liver part was not the content of the hernia sac. In English literature, one similar case has been reported in the right side [3]; the present case is the first one in the left side, and its diagnosis and treatment were performed during the same operation.
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2. Case report
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A 6-month-old baby was referred to our centre with the diagnosis of the left-sided diaphragmatic hernia. The bowel enema showed colonic herniation to the left hemithorax. Her subsequent computed tomography showed a mass that had the density of liver behind the bowel loops in the left hemithorax.
At the laparatomy, anterior, lateral and posterior parts of the diaphragm were intact. Only transverse loop of the colon was found in the left thoracic cavity inside the hernia sac through a 1x3 cm sized defect that was located lateral to the esophageal hiatus at the dome of the diaphragm. There was no solid organ in the sac. Examination of the liver showed that the left lobe was small and ended medially than normal; it was revealed as absence of the lateral segment of the left lobe. After excision of the hernia sac, a pedicle was observed between the medial border of the defect and the sac (Fig. 1)
. At the end of the pedicle, a 6x8 cm sized liver part was found in the left hemithorax below the compressed lung. No connection between the liver part and the left lung was detected. Neither membrane nor hernia sac surrounded the ectopic liver part. The appearance of the ectopic liver part resembles the lateral segment of the left lobe that was attached by artery, veins and bile duct containing pedicle going through the diaphragmatic defect to the hilus of the main liver (Fig. 2)
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Fig. 1. Excised hernia sac with ectopic liver part and its pedicle that was attached outside of the hernia sac.
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Fig. 2. Ectopic part of the liver resembles the lateral segment of the left lobe that was attached by artery, veins and bile duct containing pedicle to the main liver.
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After excision of the pedicle with the attached liver part, the diaphragmatic defect was closed. The histology of the intrathoracic liver part showed normal liver tissue.
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3. Discussion
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Ectopic liver has been reported in the abdomen, right thoracic cavity, anterior abdominal wall and omphalocele [1–9]. In those cases, one of the lobes or a small part of the liver that is found merely in the abdominal cavity or outside of the abdomen connected to the liver proper by means of a pedicle or mesentery is defined as ectopic liver. However, these cases have the main liver in its normal anatomic location. For this reason, the term of ‘ectopic liver part’ would appear to constitute a more accurate and descriptive terminology than ectopic liver.
The liver during its development begins as a ventral outgrowth of the endodermal tube and is always in close relation to the diaphragm. The major component of the developing diaphragm is the septum transversum, a mesodermal plate anteriorly located between the pericardial and abdominal cavities. It grows dorsally and fuses with the mesentery of the esophagus. The pleuroperitoneal membranes fuse with the mesentery of the esophagus medially and migrate anteriorly to join the septum transversum closing two large posterolateral openings, the pleuroperitoneal canals. The liver lobes grow rapidly with an extension dorsally which facilitates the obliteration of the pleuroperitoneal canals, so that closure of the pleuroperitoneal canals finally results at the dome of the diaphragm, corresponding to the location of the diaphragmatic defect in the present case. Final contribution from the body wall results in complete partition between the primitive thoracic and abdominal cavities. When thoracoabdominal connections are open, rapidly proliferating, pliable and fragile liver has the opportunity of extending into the developing pleural space through the pleuroperitoneal canals [4,6]. Long-term compression of the firm margins of the developing diaphragm result in complete division of the liver parenchyma into two parts which are connected only by mesenteric pedicle containing artery, veins and bile duct in order to function [4,6,7,9]. If this compression obstructs the pedicle, full separation results in atrophy of the separated intrathoracic part.
Since liver entrapment alone usually occurs on the right side of the diaphragm, ectopic liver part arises most commonly from the right lobe of the liver [4–7]. The present case most likely results from the entrapment of only the lateral segment of the left lobe. The classic left-sided congenital diaphragmatic hernia features a defect in the diaphragm with the liver, the spleen, the kidney and almost the entire gastrointestinal tract herniation to the thoracic cavity. The herniated visceras present such a large mass that it cannot be compressed by margins of the diaphragmatic defect, not allowing closure of the pleuroperitoneal canals. Thus, complete division of the herniated liver parenchyma on the left-sided diaphragmatic hernia is more difficult than on the right-sided one.
Ectopic liver parts in the thoracic cavity are usually seen without the hernia sac. Rarely, it may be concomitant with the hernia sac but not as a content of the sac, such as Ibela's [3] and the present cases. In the present case, the ectopic liver part is actually the primary abnormality and the diaphragmatic hernia is merely a secondary development. Because closing the pleuroperitoneal canal will not permit herniation of the abdominal visceras after the division of the liver lobule, the congenital defect on the diaphragm where the pedicle passes is a potential gap for herniation. Increase in the abdominal pressure results in herniation of the abdominal viscera with peritoneal hernia sac through the opening around the pedicle of the ectopic liver part.
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References
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Abstract
1. Introduction
