**2.1.3 Indications for surgical resection**

As there is no malignant potential, symptomatic disease is the only generally accepted indication for surgical resection of hemangiomas. It should again be stressed that the availability of laparoscopy should not extend the indications for operation to asymptomatic patients. If pain is the indication for surgery, a thorough diagnostic workup is imperative to rule out other sources before attributing the symptoms to the hemangioma. The indication for surgery is more clear cut for large ruptured hemangioma, with patients often presenting in shock. Because of the dire consequences of rupture of large hemangioma, some surgeons would advocate the prophylactic resection of large lesions in patients with high risk occupations in areas remote from medical care. This opinion is controversial and should not be broadly applied.

## **2.2 Focal nodular hyperplasia**

Focal nodular hyperplasia (FNH) is generally thought to arise as a hyperplastic proliferation of cells arising from an arterial malformation. This malformation may be congenital in nature such as telangiectasia or arteriovenous malformation, or may result from vascular injury (Paradis, V 2010; Wanless, IR et al 1985). Hyperplasia is thought to be a polyclonal process resulting from the hyperperfusion resulting from increased arterial flow (Gaffey, MJ et al 1996). The polyclonal nature of these lesions has significant impact on the radiographic evaluation of FNH, as it is the only common benign lesion that appears hot on Technetium sulfur colloid scan. This is from increased uptake of tracer in Kuppfer cells present within the lesion.

Hemangioma represents the most common benign liver tumor, accounting for 5-20% of liver lesions(Buell, JF et al 2010). These tumors typically occur in females in the third through fifth decades. Symptoms typically do not occur until the tumors grow relatively large (>5cm), and typically consist of abdominal pain resulting from stretching of Glisson's capsule. There have been reports of spontaneous, traumatic, or iatrogenic rupture. A rare consequence of hemangioma is a consumptive coagulopathy resulting from sequestration of platelets and clotting factors within the tumor vasculature known as the Kasabach-Merritt syndrome. There is no potential for malignant degeneration with

Hemangiomas demonstrate a typical pattern of enhancement on triple phase contrast enhanced CT. The lesion appears as a well circumscribed hypodense mass with peripheral enhancement in the arterial phase that will progress toward the center of the lesion. This pattern is typically known as centripetal enhancement. Sensitivity of triple phase CT has been reported from 75-85% with specificity of 75-100%(Trotter, JF & Everson, GT 2001). Even better results have been reported with the use of magnetic resonance imaging, with reported sensitivity and specificity of up to 95% and 100%, respectively (Semelka, RC et al 2001). Because of the highly vascular nature of these tumors, percutaneous biopsy of suspected

As there is no malignant potential, symptomatic disease is the only generally accepted indication for surgical resection of hemangiomas. It should again be stressed that the availability of laparoscopy should not extend the indications for operation to asymptomatic patients. If pain is the indication for surgery, a thorough diagnostic workup is imperative to rule out other sources before attributing the symptoms to the hemangioma. The indication for surgery is more clear cut for large ruptured hemangioma, with patients often presenting in shock. Because of the dire consequences of rupture of large hemangioma, some surgeons would advocate the prophylactic resection of large lesions in patients with high risk occupations in areas remote from medical care. This opinion is controversial and should not

Focal nodular hyperplasia (FNH) is generally thought to arise as a hyperplastic proliferation of cells arising from an arterial malformation. This malformation may be congenital in nature such as telangiectasia or arteriovenous malformation, or may result from vascular injury (Paradis, V 2010; Wanless, IR et al 1985). Hyperplasia is thought to be a polyclonal process resulting from the hyperperfusion resulting from increased arterial flow (Gaffey, MJ et al 1996). The polyclonal nature of these lesions has significant impact on the radiographic evaluation of FNH, as it is the only common benign lesion that appears hot on Technetium sulfur colloid scan. This is from increased uptake of tracer in Kuppfer cells present within

**2.1 Hemangioma** 

hepatic hemangioma.

**2.1.2 Diagnostic evaluation** 

hemangiomas is contraindicated.

be broadly applied.

the lesion.

**2.2 Focal nodular hyperplasia** 

**2.1.3 Indications for surgical resection** 

**2.1.1 Epidemiology and presentation** 

### **2.2.1 Epidemiology, radiographic evaluation, and presentation**

FNH is typically an incidentally discovered lesion in women of late child bearing age, presenting most commonly from age 30 to 50. The female to male ratio has been reported at up to 8:1 (Mortele, KJ & Ros, PR 2002). Unlike hepatocellular adenoma, FNH is not influenced by oral contraceptive use. The radiographic appearance of focal nodular hyperplasia is typically diagnostic. On triple phase computed tomography, FNH will show transient enhancement on arterial phase. On delayed imaging, the characteristic central scar then becomes hyperenhancing. This central scar represents the vascular pedicle of the lesion and is pathognomonic. The most common diagnostic difficulty is distinguishing FNH from adenoma, which may best be achieved by contrast enhanced MRI. In this setting, sensitivity and specificity can reach 97% and 100%, respectively (Terkivatan, T et al 2006).

 On histologic examination, FHN consists of benign hepatocytes arranged in a nodular pattern that are separated by fibrous septae originating in the central scar. Steatosis within the lesion may be evident (Paradis, V 2010). FNH is asymptomatic in upwards of 80% of cases (Buell, JF et al 2010). In very rare instances, these lesions may present with hemorrhage. There are no reported cases of malignant degeneration of FNH thus far. Because of this, there is no indication for resection of asymptomatic lesions, regardless of the size and number of lesions. Surgical resection is reserved for the rare cases in which the lesion is symptomatic or when the diagnosis is not secure.

#### **2.3 Hepatocellular adenoma**

Hepatic adenoma is a less common benign hepatic neoplasm, arising most commonly in women of child bearing age. There is a strong association between development of these lesions and oral contraceptive or androgenic steroid use. While the incidence is 0.1 per year per 100,000 patients who don't use oral contraceptives, there is a marked increase to up to 4 per 100,000 oral contraceptive users (Paradis, V 2010). The introduction of modern contraceptives with lower estrogen content has led to a decrease in incidence (Rooks, JB et al 1979). Less common risk factors for the development of hepatocellular adenoma include glycogen storage disease type I and type III (Micchelli, ST et al 2008)

#### **2.3.1 Radiographic features**

Though typically presenting as solitary lesions, adenoma may also be present as multiple lesions. Hepatic adenomas can grow quite large, with tumors of up to 30cm reported in the literature. Ultrasonography typically lacks diagnostic utility for adenomas, which can range from hypo to hyper-echoic. Reported sensitivity of ultrasound is only around 30%(Di, SM et al 1996). The CT appearance is that of a discrete, hypodense lesion showing enhancement on arterial phase followed by washout on later images. T1 weighted MRI will show a hypoto hyperintense lesion, while T2 images will show a lesion that is more isointense. Enhancement with gadolinium contrast is typically present on the arterial phase, with rapid washout in the venous phase. The fat content of these lesions creates a typical decrease in intensity on fat-suppressed MRI images (Motohara, T et al 2002).

#### **2.3.2 Clinical presentation**

Patients with hepatocellular adenoma are more likely to present with symptomatic disease than those with FNH. Epigastric or right upper quadrant pain is present in 25-50% of patients (Buell, JF et al 2010). Spontaneous hemorrhage is also relatively common with these

Laparoscopic Liver Resection 67

of 64 patients suffered any form of complication from NRH. Specific treatment for NRH is not needed. Diagnosis is made on liver biopsy, with reticulin staining being particularly helpful in identifying the changes of hyperplasia. Therapy, instead, is directed at treating

Inflammatory pseudotumor of the liver is a benign reactive process, the pathogenesis of which is unclear. In the majority of cases in the literature, an infectious agent was found to be the causative agent. Symptoms, when present, are generally nonspecific including body pain, fever, weight loss, leukocytosis, and elevated transaminases. CT findings are generally not specific for the diagnosis, although spontaneous regression on followup imaging in 4-6 weeks is commonly reported to occur (Seki, S et al 2004). Histological features include replacement of liver parenchyma by densely hylanized collagenous tissue and chronic inflammatory infiltrates. These features are missed on FNA, making core needle biopsy critical for accurate diagnosis (Tsou, YK et al 2007). In a review of eight cases, Tsou et al have suggested that inflammatory pseudotumor may best be thought of as a variant of a healing liver abscess. Thus, treatment consists of antibiotic therapy and nonsteroidal antiinflammatory drugs. With appropriate therapy, the lesion can be expected to spontaneously regress. Surgical therapy is thus reserved for cases with severe symptoms or when

The majority of benign liver lesions are asymptomatic, leaving surgical resection as an appropriate therapy only in cases of symptomatic disease that is clearly attributable to the lesion, or when the diagnosis remains in doubt following appropriate workup. The exception is for hepatocellular adenoma, where the risk of malignant degeneration

There are three commonly used patient positions employed in laparoscopic liver resection: supine, lateral decubitus, and the so-called French position in which the patient is supine with the legs in stirrups and the surgeon is positioned between the patient's legs. The appropriate position is determined based on the location of the tumor, and the surgical technique to be employed. The French position has the advantage of allowing the surgeon to operate with both hands while assistants can retract from either side of the table. The supine position is best employed when approaching lesions on the left lobe or right anterior sector of the liver. The lateral decubitus position places the patient recumbent on their left side at an angle of sixty degrees. This position allows access to the posterior segments of the right liver, as the left side down positioning prevents the liver from falling dependently into the operative field. When a hand port is to be employed, it is generally placed in the right upper

The use of low CVP anesthesia has been a critical factor in the improved safety of modern hepatic surgery. This technique mandates the use of central venous catheters and arterial lines for patient monitoring. During the parenchymal transection phase, central venous

mandates resection for lesions larger than 5cm or cases occurring in men.

quadrant as dictated by the position of the tumor being resected.

**2.5.2 Anesthesia and intraoperative care** 

the underlying disorder or withdrawing the offending medication.

**2.4.3 Inflammatory pseudotumor** 

malignancy is unable to be reliably excluded.

**2.5 Technical considerations for resection** 

**2.5.1 Patient positioning** 

lesions, occurring in over 20% of patients. These complications are more likely to occur in men and with lesions greater than 5cm in diameter (Dokmak, S et al 2009). Perhaps the most feared complication of hepatocellular adenoma is malignant degeneration. The risk has been reported in the range of 8-10%(Dokmak, S et al 2009; Paradis, V 2010). Although 5cm is the generally accepted size at which malignant degeneration becomes a concern, cases have been reported in lesions as small as 4cm (Micchelli, ST et al 2008). There is also a greater risk of malignant degeneration in males and in patients with the metabolic syndrome. Malignancy within adenomas is typically discovered only after surgical resection.

### **2.3.3 Management**

In the case of small adenomas in the setting of oral contraceptive use, a period of observation following the cessation of contraception is warranted. Surgical resection in this setting is then reserved for lesions which fail to regress or continue to grow after stopping the offending medication. As with other benign lesions, symptomatology that can clearly be attributed to the adenoma is also an indication for surgical resection. The presence of multiple adenomas, or adenomatosis, is an arbitrary distinction rather than a distinct pathologic subtype, thus indications for resection are the same as for solitary adenoma. Because of the well defined risk of malignant degeneration, there are also cases where resection of asymptomatic lesions is warranted. Generally accepted criteria include adenomas greater than 5cm in size, or any adenoma in a male, regardless of size (Dokmak, S et al 2009).
