Keywords
accessory hepatic lobe - torsion of accessory liver lobe - omphalocele
Introduction
Cases of congenital accessory hepatic lobe torsion (AHL) are largely unheard of with
only 22 reported cases in children, out of which there were only 7 reported in infants,
in English literature as of 2017.[1]
AHL may be sessile with a wide base of continuous hepatic parenchyma connected to
the liver proper, appearing as small tongue-like projections from the surface of the
liver (i.e., Riedel's lobe) or rarely exist as a pedunculated mass of hepatic parenchyma
attached to a vascular pedicle.[2] Most of the cases are asymptomatic. When pedunculated, AHL can undergo torsion resulting
in ischemia, which can then present as an acute abdomen. To help identify and properly
treat such cases we aim to provide more insight on the subject.
We present a case of torsion of the AHL with an embedded gallbladder, embedded in
it, in an infant.
Case Report
An 11-month-old boy weighing 8 kg presented to the emergency department with severe
pallor, cyanosis, and signs of respiratory distress. He was a known G6PD-deficient and had a history of omphalocele repair in the neonatal period. On examination,
he was in distress, mildly cyanotic, afebrile, and not jaundiced. His vital signs
were: heart rate (HR): 158 bpm, respiration rate: 40 bpm, blood pressure: 85/40 mm
Hg, and temperature: 35.3°C. The examination of the respiratory system showed the
presence of doubtful bilateral basal crepitations.
On abdominal examination, there was soft distention with a palpable mass occupying
the right half of the abdomen, extending to the umbilicus, which was tender and there
was no blood or mucus on per rectal examination. Laboratory investigations revealed
a white cell count of 36 × 103/µL, hemoglobin: 9.7 g/dL, serum sodium, potassium, and creatinine levels were normal,
the alanine aminotransferase (ALT) value was 48 U/L, serum bilirubin, and alkaline
phosphatase levels were normal. The C-reactive protein was normal, and the venous
blood gas analysis showed a pH of 7.1, Po
2: 36%, Pco
2: 73%, HCO3: 22.7, and base excess of −7.5. Within 3 hours the patient became paler, and the
hemoglobin dropped to 6 g/dL. He subsequently received an urgent blood transfusion
and was started on antibiotics; chest X-ray was unremarkable.
On abdominal ultrasound, a 10 × 8 cm mass was noted. Evidence of marked ascites was
present, and the gallbladder was distended.
A computed tomography scan of the abdomen with oral and intravenous contrast confirmed
a large high density (100 HU) midline mass measuring 7.8 × 8.9 × 9.4 cm ([Fig. 1A–C]).
Fig. 1 (A–C) White arrows show the accessory hepatic lobe and the black arrows show the embedded
gallbladder.
This gave the initial impression of a volvulus involving a lobe of the liver and gallbladder
or internal herniation. Moderate amount of free fluid was noted in the subhepatic,
right paracolic gutter, and the pelvis.
An urgent exploratory laparotomy was then performed through an upper transverse abdominal
incision. We discovered a severely congested hepatic lobe with the gallbladder in
situ. Due to the presence of the gallbladder, we presumed that this was the right
lobe of the liver ([Fig. 2A]).
Fig. 2 Operative pictures: (A) Dusky Congested accessory liver lobe with the congested gallbladder (white arrow)
embedded in it. (B) The liver lobe regaining normal color after untwisting the pedicle (white arrow).
This was found to be under torsion on an abnormally long pedicle. Also, a lobe of
the normal liver was found in the location of the right lobe without the gallbladder
attached to it. Following this observation, the lobe was untwisted, and signs of reperfusion
were noted. The bowel was normal in color, the duodenojejunal flexure was located
normally, but the cecum was mobile ([Fig. 2B]).
On the postoperative day 1, the patient showed signs of recovery inferred by his improving
blood gases and vital signs, but 24 hours later he again suddenly became pale, tachycardiac
with an HR of 185 bpm, and a concurrent drop in hemoglobin from 10 to 6 g/dL. The
abdomen became tense again, and an urgent ultrasonography was done but was inconclusive
regarding blood flow to the affected part of the liver. Liver function tests revealed
marked elevation of ALT level up to 3,854 U/L. An urgent relaparotomy was performed,
and the previously torted hepatic lobe was found to be under torsion again; with a
dusky hue and patchy necrosis, therefore excision of the ischemic torted AHL along
with the gallbladder was performed. The remaining lobes of the liver were noted to
have an independent pedicle containing the portal triad. The patient was given blood
products and was continued on antibiotics. On ultrasound 1 after relaparotomy, the
liver had normal size and a uniform texture with normal hepatic and portal veins.
There was no evidence of thrombus formation, and the common bile duct and intrahepatic
biliary radicles were not dilated. The patient gradually recovered and was discharged
in good condition 12 days after admission. He remained asymptomatic on follow-up after
14 months.
Discussion
The AHL by definition is a developmental congenital anomaly of the hepatic bud that
arises from the endodermal caudal foregut.[3] There are differing ways to classify this entity,[4]
[5] largely it is classified based largely on the size (10–30 g) and location of the
lobe (attached to the liver or ectopic) or the presence of a capsule and biliary drainage
system.[3] The viability is assessed by the presence of the portal triad in the AHL.[5]
Similar to previously reported cases, the diagnosis of the AHL torsion was only definitively
made intraoperatively. As of 2017, only 22 cases have been reported in children regarding
this anomaly with 7 cases reported in infancy.[1] There seems to be a male predominance of AHL in infancy whereas in females AHL was
often an incidental finding. The reason for this phenomenon remains unknown.[1]
[4] Imaging techniques without a high index of suspicion make the preoperative diagnosis
difficult. In this case, due to the history of an omphalocele and the presentation
of an acute abdomen and a palpable mass, there was reasonable indication to suspect
AHL pathology.[3]
Our patient presented in a very sick state probably as the extent of torsion was severe,
and the gallbladder was included in the torted lobe. Depending on the location and
duration of torsion of the AHL, it can present with various symptoms. A pedunculated
AHL carries a higher risk of torsion than the other types of AHLs. Moreover, severe
congestion and insufficient blood supply may lead to rupture of larger vessels.[2] Strangulation of the vascular supply to the liver due to the twisting of the mesentery
of a large AHL may lead to hepatic ischemia necessitating transplantation.[6] However, our patient had a successful outcome, like another case,[7] which is attributed to the prompt recognition and the surgical intervention performed.
The torted AHL in our patient was not necrotic and had regained color upon untwisting
the lobe, yet it underwent torsion again and had to be excised the following day.
It can be postulated that an excision is a good option as the primary approach instead
of trying to preserve any seemingly viable liver tissue after it has been untwisted.
However, we cannot rule out that fixation of the untwisted lobe would have been successful
too in our case.
Conclusion
Without a high index of suspicion, the diagnosis of an AHL is difficult before surgical
exploration. When discovered, the excision during initial laparotomy is a good option.
