Accessory Liver Lobes Research Articles

Anatomy and Imaging of Accessory Liver Lobes: What Radiologists Should Know

Although the liver may present a range of congenital anomalies, often involving shape irregularities or the number of lobules, less common variations include the presence of accessory liver lobes (ALL), consisting of a supernumerary lobe of normal hepatic parenchyma in continuity with the liver. This paper reviews the embryology, frequency, anatomy, and types of ALL. Furthermore, we describe computed tomography and magnetic resonance imaging findings in a range of such cases, including those simulating disease or presenting with complications. Knowledge about ALL may facilitate imaging interpretation of such alterations, avoiding inappropriate additional work-up and unnecessary interventions.

A Comprehensive View into a Novel, Accessory Liver Lobe

Precise clinical knowledge of liver anatomy is required to perform a hepatectomy, in both open and laparoscopic surgery. Accessory liver lobes (ALL) are anatomical variations involving supernumerary lobes in the liver. Although their origin is not entirely understood, hypotheses for the embryological processes resulting in an ALL include hyperplastic anomaly during embryological development or formation because of increased intraabdominal tension from trauma or surgery. In most cases, the accessory lobe is located inferior to the liver. Riedel’s lobe is the best-known example of an accessory lobe, corresponding to hypertrophy of liver segments V and VI. In this report, we presented the case of an elderly female cadaver who showed an atypical ALL left variant attached through an accessory ligament. Therefore, we discuss the gross morphology, histopathology, and clinical and surgical implications to improve future patient outcomes.

Case Report: The Fifth Liver Lobe; A Hybrid Left‐Sided Anatomical Variation of Accessory Liver Lobes

Accessory liver lobes (ALL) are supernumerary lobes in the liver. Although their origin is not completely understood, they appear to be due to a congenital anomaly caused by hyperplasia, trauma, and/or surgery. Two types of accessory lobes are documented in the literature: continuous and ectopic accessory lobes, differing in that the ectopic lobe is anatomically separate from the normal liver as opposed to the continuous subtype. Although rare, several reports exist with Riedel’s Liver Lobe being among the most well‐known. In these cases, the ALL is normally continuous with the right side of the liver and exists as either a sessile or pedunculate attachment. In our case, a rare ALL was found on the left lobe during a routine dissection of a male cadaver. However, structurally it is different from both continuous and ectopic ALL in that it is not joined to the liver via a connecting stalk nor is completely separate. Rather, this variant, a 7.5cm long ‐ 7.0cm wide‐2cm tall ALL displays a ligamentous attachment alongside the lateral edge of the left lobe. Most cases of ALL are asymptomatic and discovered incidentally. In imaging studies, ALL may be confused with tumors leading to misdiagnosis and errors in treatment. Although infrequent, there are reports of complications of ALL including infarction, hemorrhage, biliary atresia, and gallbladder torsion. Hypotheses for the embryological process of an ALL include heteroplastic embryological development as well as increased intraabdominal tension. Awareness of this variant will help decrease risk of iatrogenic injury in suspected ALL cases.

Akcesorni i ektopični lobus jetre kod istog pacijenta - prikaz slučaja

Accessory liver lobes (ALL) are defined as supranumerary liver lobes, composed of normal liver parenchyma in continuity with the liver, in contrast to ectopic liver lobes (ELL) that have no anatomical continuity with the normal liver. Case report: In this article we report on a rare radiological diagnosis of an synchronous accessory and ectopic liver lobe using ultrasonography (US) and computed tomography (CT). A 59-year-old female with no symptoms was admitted to our hospital due to preventive exam. Abdominal ultrasonography revealed a high echoic 6 cm x 5 cm soft tissue area in right anterior subhepatic space with distinct margins, a uniform echo and blood flow and was suspected to be abdominal tumor. An enhanced abdominal computed tomography (CT) showed the irregular 65 mm x 48 mm x 32 mm mass in the right hypochondrium below IV and V liver segment with clear margins, a uniform density, texture and contrast enhancement as normal liver tissue. In same patient CT also showed small 16 mm x 12 mm mass in posterior mediastinum in right retrocrural space so diagnosis of accessory and ectopic liver lobe was confirmed. An accessory liver lobe is adjacent and attached to the liver by its own mesentery, while an ectopic liver lobe is one that is completely detached from the normal liver parenchyma. Conclusion: Ultrasound can show mass in the abdomen, which is most commonly in the subhepatic area, but very rarely can initially diagnose ALL or ELL due to different echogenicity of the liver parenchyma in different acoustic windows. In the case of an atypical CT presentation, an MR examination of the abdomen is indicated but it is very rarely. Fast and accurate radiological diagnosis of ALL and ELL is important in the prevention of unnecessary invasive diagnostic procedures such as laparotomy and thoracotomy which are needed only in cases of complications.

Morphometric analyses of small accessory liver lobes using radiological imaging

AimTo investigate the prevalence and morphometric characteristics of small accessory liver lobes using computed tomography (CT) and magnetic resonance (MR) images. Material and methodsThe study population comprised 3269 patients (1671 men and 1598 women; mean age, 67.1 ± 15.2 years) who had undergone abdominal CT examination. Small accessory liver lobes were identified after verification of their continuity with the liver parenchyma on CT images. Their imaging characteristics were analyzed and presented. ResultsThirty-five small accessory liver lobes in 33 patients (1.01%; 25 men and 8 women, 71.0 ± 11.7 years) were identified. Thirty-one patients (93.9%) had solitary lesions most frequently identified on liver segment 6 (80.0%) with the mean size 9.6 ± 4.8 mm. These showed iso (62.9%), hyper (28.6%), or hypoattenuation (8.6%) on unenhanced CT. Enhanced CT images were available for 29 lesions. Enhancement of 12 lesions (41.4%) was similar to that of the liver parenchyma, whereas 17 lesions (58.6%) showed poor enhancement. MR images were available for 10 lesions, which showed hyperintensity (50.0%) on T2-weighted images and poor enhancement (50.0%). The characteristics of other lesions were similar to those of the liver parenchyma. During observation (mean, 77.0 months; n = 29), 19 lesions remained the same size (65.5%), 5 new lesions increased size (17.2%), and 5 showed reduced size (17.2%). ConclusionSmall accessory liver lobes, commonly located on segment 6, were frequently observed and did not necessarily show the same findings as the liver parenchyma. Time-dependent morphological changes were observed in approximately one-third of the lesions.

Accessory hepatic lobes in the pediatric population: A report of three cases of torsion and literature review

Abstract Congenital liver anomalies are uncommon. Symptomatic accessory hepatic lobes (AHL), either in continuity with the liver or ectopically located, are even less common. AHL have been reported in individuals spanning from neonates to octogenarians and are typically asymptomatic, however when symptomatic often require surgical intervention. We report three new cases of AHL in children (mean = 14.6 years). All three presented with sudden onset of abdominal pain and were diagnosed preoperatively by imaging findings. All three patients had symptom resolution following resection of the torsed accessory liver lobes. We report here the largest series of pediatric AHL torsion at a single institution to date, review the classification schemes, identify diagnostic imaging findings, and summarize associated congenital disorders that should raise suspicion for accessory hepatic lobes.

Accessory liver lobes: Anatomical description and clinical implications

Accessory liver lobes are a rare condition and appear to be due to excessive development of the liver. The presence of an accessory hepatic lobe is often diagnosed incidentally and sometimes revealed if it develops torsion, especially in pedunculated forms. In most cases, the accessory lobe is located below the liver, i.e., infrahepatic. Riedel's lobe is the best-known example of an accessory lobe, corresponding to hypertrophy of segments V and VI. While accessories lobes can simulate tumors, there have also been reports of hepatocellular tumor(s) that developed in these accessory lobes. Based on a review of the literature, this update focuses on accessory hepatic lobes.

Some interesting morphological features of liver lobes in Mumbai population

Introduction: Liver is the largest gland in the body mainly situated in the right upper quadrant of the abdomen. Abnormalities of liver are rare. Common abnormalities are irregularities in form, occurrence of one or more accessory lobes, fissures or abnormal ligaments. Rare abnormalities include atrophy, or complete absence of one of the lobes. Although the segmental anatomy of the liver has been extensively researched, very few studies have dealt with the surface variations of the liver. Accessory lobe may be confused with tumour. Accessory fissure may mimic internal trauma at the time of the post-mortem study. Aim: Present study was carried to find out the morphological variations of liver lobes occurring in Mumbai population. Methods & Materials: The materials used for present study comprised of formalin fixed 50 adult livers. Results & conclusion: In the present study we found accessory liver lobes in 3 cadavers i.e. 6 %, atrophy of left lobe in 15 cadavers i.e. 30 %, accessory fissures in 21 cases i.e.42%.There is also abnormal connection between left lobe and quadrate lobe in 14% cases. The findings of study may be helpful to radiologist and surgeons respectively, to avoid possible errors in interpretations and subsequent misdiagnosis, and for planning appropriate surgical approaches.

Accessory hepatic lobe

The aim of the present communication was to describe an accessory hepatic lobe in two patients and to outline the significance of the timely identification of this very rare anatomic variation for the clinical practice. In the course of right hemihepatectomy, accessory liver lobes were detected in two patients. Their diagnosis was confirmed by histopathology and cholangiography. Both accessory hepatic lobes arose from the left liver segments. The first lobe was detected in a 56-year-old male operated on for a retroperitoneal liposarcoma. It amounted to 15% of the standard liver volume and was attached to liver segments 2 and 3 by a stalk. The second accessory lobe was found out in 45-year-old female operated on for a colon cancer and synchronous liver metastases. It was less than 15 g in weight and attached to the main liver by a mesentery as its bile duct drained into an extrahepatic duct. The accessory hepatic lobes require timely diagnosis. They should be kept in mind in cases with acute surgical abdomen.

Accessory Lobe of Right Liver Mimicking a Pulmonary Tumor in an Adult Male

We describe a rare case of ectopic liver tissue in the right thoracic cavity. A 39-year-old man with a suspected lung tumor underwent thoracotomy. The intraoperative finding revealed an accessory liver lobe connected to the right lobe of the liver by a small pedicle that pierced the diaphragm. A pathologic evaluation confirmed the specimen to be hepatic tissues. In retrospect, the correct diagnosis of accessory liver could have been achieved using appropriate radiologic investigations if this possibility had been considered.

Torsion and Infarction of an Accessory Liver Lobe

Accessory lobes of the liver (ALL) may be congenital or acquired and are usually of no clinical significance. Torsions of the ALL are exceedingly rare and most are incidental findings at laparotomy, autopsy and in the course of investigation radiological investigations. A total of 17 infant and adult cases have been described previously in the medical literature. Most cases described since 1925 have been diagnosed at laparotomy, we report the 18th case of torsion of the accessory lobe of the liver in an elderly female which, despite all radiological interventions, required laparoscopy for diagnosis. We conclude that torsion of the accessory lobes of the liver is a rare finding; radiological imaging does not reveal the diagnosis and most are found at laparotomy. Laparoscopy may aid in the diagnosis of torsion of accessory liver lobes. If pain persists, we advocate the use surgical intervention with or without cholecystectomy.

腹腔鏡検査にて診断した肝副葉の7例

Accessory liver lobe is attached to main liver, and different from ectopic liver which is detached from main liver. Accessory liver lobes are incidentally noted at operation or necropsy in most cases. We reported 7 cases with accessory liver lobe diagnosed by laparoscopy. The cases were of 22 to 63 years old, including 6 females and one male. The biopsy diagnosis of main liver was chronic hepatitis in 4 cases, acute hepatitis, drug-indused hepatitis and autoimmune hepatitis in 1 case each. These accessory liver lobes were attached to quadrate lobe (S4) in 4 cases, and left liver lobe (S3) in 3 cases. Accessory liver lobes measured 3mm minimum and 10mm maximum in size. In shape, they were tongue-like in 3 cases, semioval and hemispherical in 2 cases each. All of them could not be demonstrated by ultrasonography and CT, and were asymptomatic.

Observations on the liver of the chicken following aflatoxin B1ingestion

During a series of experiments it was noted that a proportion of birds sacrificed after ingesting aflatoxin B1 had small accessory liver lobes which appeared less abnormal in colour. No histopathological differences were observed but specific activities of several hepatic enzymes were less depressed in the accessory lobe than in the remainder of the liver.