**2. Benign disease**

Benign liver tumors represent a diagnostic and therapeutic challenge. Traditionally, a highly conservative approach to benign hepatic tumors has been favored, owing to the historically high morbidity and mortality associated with open liver surgery. As operative and anesthetic techniques have improved, these hurdles have come down. Despite the increased safety of hepatic surgery, the indications for resection of benign hepatic tumors have changed little: symptomatic lesions, asymptomatic lesions at high risk of rupture or malignant degeneration, and inability to exclude malignancy nonoperatively. Because of concerns over oncologic adequacy, benign lesions represent the ideal starting point for a laparoscopic liver surgery program. Despite the attractiveness of minimally invasive surgery; however, surgeons should be cautioned that the ability to perform a laparoscopic resection should not change the indications for operation.

Laparoscopic Liver Resection 65

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

 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

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

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

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

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

lesion is symptomatic or when the diagnosis is not secure.

glycogen storage disease type I and type III (Micchelli, ST et al 2008)

intensity on fat-suppressed MRI images (Motohara, T et al 2002).

**2.3 Hepatocellular adenoma** 

**2.3.1 Radiographic features** 

**2.3.2 Clinical presentation** 

and specificity can reach 97% and 100%, respectively (Terkivatan, T et al 2006).

## **2.1 Hemangioma**

#### **2.1.1 Epidemiology and presentation**

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 hepatic hemangioma.
