sensitivity is usually associated with reduced specificity. Limitations of 18F-FDG-PET include its limited

availability, high cost, limited access to specialized techniques, and lack of expertise to interpret the

results. Therefore, from a practical clinical perspective, CT, MRI, or both should be the first-line

modalities for characterizing hepatic lesions and 18F-FDG-PET can be used as the second-line modality

for evaluating the metabolic features of the lesion or the presence of extrahepatic disease. Ultrasound

should be used as a routine diagnostic tool throughout the perioperative period. It is mandatory for

hepatobiliary surgeons to acquire expertise in ultrasonography.

Figure 60-1. Couinaud segmental anatomy of the liver. In Couinaud theory, the liver is divided in to two hemilivers, four sectors,

and eight segments according to the portal venous ramification pattern. Three major hepatic veins represent the posit

sensitivity is usually associated with reduced specificity. Limitations of 18F-FDG-PET include its limited

availability, high cost, limited access to specialized techniques, and lack of expertise to interpret the

results. Therefore, from a practical clinical perspective, CT, MRI, or both should be the first-line

modalities for characterizing hepatic lesions and 18F-FDG-PET can be used as the second-line modality

for evaluating the metabolic features of the lesion or the presence of extrahepatic disease. Ultrasound

should be used as a routine diagnostic tool throughout the perioperative period. It is mandatory for

hepatobiliary surgeons to acquire expertise in ultrasonography.

Figure 60-1. Couinaud segmental anatomy of the liver. In Couinaud theory, the liver is divided in to two hemilivers, four sectors,

and eight segments according to the portal venous ramification pattern. Three major hepatic veins represent the position of

intersectoral plane (called scissura). LHV, left hepatic vein; MHV, middle hepatic vein; RHV, right hepatic vein.

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Figure 60-2. Three-dimensional shape of the intersegmental plane. Top left: Lateral view of the right hemiliver. The right lateral

sector indicated by the dark-gray color and an interdigitated demarcation line is visible on the liver surface (white dotted line).

Segment VIII (S8) protrudes dorsolaterally (arrows) relative to Segment V (S5). Top right: Dorsolateral view of the cut surface after

a simulated right lateral sectorectomy. The right scissure exhibits a concave shape because of the protrusion of Segment VIII (H,

head; L, left; P, posterior). Axial computed tomographic image (bottom left) and diagram (bottom right) illustrating that the

intersegmental border between Segments VIII and VII is not compatible with the plane of the right hepatic vein. The posterolateral

part of the right hepatic vein in Segment VIII is presented. (Adapted from Shindoh J, Mise Y, Satou S, et al. The intersegmental

plane of the liver is not always flat–tricks for anatomical liver resection. Ann Surg 2010;251(5):917–922.)

In radiographic evaluation, the tumor location is described according to Couinaud anatomy for liver

segments.35 In Couinaud theory, the liver can be divided into two hemilivers, four sectors, and eight

segments defined as the territories of the first-, second-, and third-order portal branches, respectively

(Fig. 60-1). Because typical systematic surgical resection follows the segmental anatomy of the liver,

the location of tumor should be defined based on accurate understanding of the segmental anatomy of

the liver. “Segment” is defined as a territory of a portal branch and its actual three-dimensional shape is

not simple, despite depictions in many surgical textbooks.36 For example, Segment VIII usually

protrudes craniolaterally, overhanging the right hepatic vein (Fig. 60-2). Accordingly, a hepatic lesion

located just to the cranial side or posterolateral side of the right hepatic vein is a Segment VIII tumor,

which can be easily confirmed by tracking the nearest portal branches on CT images.

BENIGN HEPATIC NEOPLASMS

Cystic Lesions

Simple Cyst

The distinction between solid and cystic lesions is clinically important, as the vast majority of cystic

lesions of the liver are benign in behavior. The majority of the incidentally diagnosed cystic lesions are

simple cysts, which have no malignant potential and rarely become symptomatic. However, surgical

treatment is considered for symptomatic giant cysts stretching the liver capsule or compressing the

adjacent organs. Laparoscopic unroofing (Fig. 60-3) may be the ideal approach for these lesions, which

has acceptably good outcomes and a negligible recurrence rate in experienced hands.37

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Figure 60-3. A huge hepatic cyst observed in the right hemiliver (left). Laparoscopic unroofing (right) was performed for this

patient to relieve the abdominal pain associated with distension of the liver capsule. Cystic fluid was first suctioned and then the

anterior wall of the cyst (*) was resected with an energy device. (Images courtesy to Dr. Yasuji Seyama.)

Polycystic Liver Disease

Polycystic liver disease (PLD) is a rare presentation of cystic liver lesions and can be difficult to

manage.38 Approximately 80% to 90% of PLD cases represent an autosomal dominant disease associated

with polycystic kidney disease. In these patients, renal failure frequently occurs due to destruction of

the kidney by multiple cysts. Although patients with PLD rarely develop hepatic failure regardless of

the marked change in the distorted liver on imaging studies (Fig. 60-4), various symptoms caused by

distention of the liver, stretching of the diaphragm, or compression of the adjacent organs require

therapeutic intervention. Treatment for PLD should be performed in a stepwise fashion. Ultrasonically

guided puncture of the cysts should be the first choice to decompress the distended cysts and drain the

fluid. If percutaneous aspiration is not effective, the next option is laparoscopic fenestration of the cysts.

Liver resection or transplantation should be the final treatment option. A limited number of patients

require liver transplantation due to the progressive destruction of liver parenchyma and hepatic

dysfunction. However, liver transplantation for PLD is a challenging procedure due to severe adhesion

and huge liver size, usually causes major bleeding, and requires a large amount of transfusions

especially for patients with a history of multiple interventions or surgery for PLD. A recent report

suggested that a history of open intervention is a strong risk factor for severe postoperative

complications, longer hospital stay, and poor long-term outcomes after transplantation.39 Therefore, a

minimally invasive approach is preferable for disease-directed interventions for PLD as long as this

approach is viable.

Figure 60-4. CT image of a patient with polycystic liver associated with autosomal dominant polycystic kidney disease. The liver is

markedly distended due to destruction of the liver by multiple cysts and compensatory regeneration of hepatic parenchyma.

However, the hepatic function is maintained with an albumin level of 2.8 g/dL, bilirubin level of 1.5 mg/dL, and INR of 1.12,

with slight ascites and no evidence of encephalopathy (Child–Turcotte–Pugh class B).

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Biliary Cystadenoma

3 Most hepatic cysts are asymptomatic, and surgical resection is indicated only for lesions for which

there is concern for malignancy or malignant potential. Wall enhancement in contrast-enhanced CT,

serrated or septated wall visualized by ultrasound, or rapid increase in size suggests malignant potential

of a lesion. Biliary cystadenoma is the common cystic lesion with malignant potential, accounting for

5% of all cystic lesions in the liver.40 These lesions arise from the biliary epithelium and typically

present in middle-aged women. Because it is difficult to distinguish between cystadenoma and

cystadenocarcinoma (Fig. 60-5) and because cystadenoma has a propensity toward local recurrence and

malignant degeneration to cystadenocarcinoma,41,42 surgical resection is indicated primarily when

biliary cystadenoma is suspected.

Solid Lesions

Solid lesions should be handled with care because benign lesions are sometimes difficult to discriminate

from malignant tumors.

Figure 60-5. CT image of a cystadenocarcinoma. A multicystic lesion with an enhanced intracystic papillary component was

observed (arrow).

Hemangioma

Hemangioma is the most common benign lesion observed in the liver; the estimated prevalence is 3% to

20%.43 Most hemangiomas are identified in individuals aged 40 to 60 years and appear to be more

common in women, with a female-to-male ratio of 2:1.44 Grossly, hemangiomas are well-circumscribed

and compressible lesions. Histopathologically, multiple blood vessels lined by endothelial cells are

present.45 The majority of hemangiomas are small asymptomatic lesions that can be managed

nonsurgically. Spontaneous or traumatic rupture of hemangioma in exceptional cases has been reported,

but the risk of rupture is considered very low. Therefore, the majority of these cases can be left

untreated with regular follow-up imaging studies.

Accurate radiographic diagnosis of a hepatic hemangioma is important, as establishment of this

diagnosis requires no additional intervention for the majority of patients. For diagnosis, a dynamic

study is the most important for characterizing the hemodynamics in a lesion. Contrast-enhanced CT

demonstrates a typical pattern of nodular enhancement from the periphery with central filling on

delayed images (Fig. 60-6). Contrast-enhanced MRI also shows similar patterns in dynamic studies, and

a very high intensity in T2-weighted images is suggestive of hemangioma. A diagnosis of hemangioma

should be made based on these radiographic findings. Although biopsy is not absolutely contraindicated,

a fatality from uncontrollable bleeding has been reported, so unnecessary biopsy should be avoided.46

Surgical resection is warranted in the setting of abdominal symptoms,47–49 spontaneous rupture,50

rapid growth of the lesion,51 or coagulopathy due to Kasabach–Merritt syndrome. Elective surgical

treatment is accomplished by either enucleation or formal hepatic resection. Enucleation is often easily

performed because hemangiomas are exophytic to some degree and a pseudocapsular plane can be

developed efficiently. Hemangiomas typically have limited outflow and the internal pressure may be

high. Early ligation of the feeding arteries, especially in patients with large hemangiomas, is a key

point, as the size reduction caused by the decompression is technically beneficial for surgical

manipulation and resection.

Focal Nodular Hyperplasia

Focal nodular hyperplasia (FNH) is the second most common benign neoplasm of the liver. A clinical

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