الفهرس 
EPIDIMIOLOGY OF BENIGN LIVER TUMOURSOnly 14 pages are availabe for public view
 |  | from | 194 |  |  |
| | | from | 194 | | |
Abstract
Benign liver tumors are increasingly being diagnosed as a result of the widespread use of ultrasound, computed tomography and magnetic resonance in the evaluation of patients with non-specific abdominal symptoms.
These tumors are derived from the hepatocytes, bile duct epithelium, and endothelial cells. There are other cell systems in the liver, including connective tissue and muscle cells, macrophages, and neuroendocrine cells
Hepatic haemangioma is the commonest benign tumor of the liver, and has been reported in 0.4–20% of cases, Haemangiomas can occur in individuals of any age. Such tumors frequently occur in middle-aged women. Focal nodular hyperplasia (FNH) accounts for 8% of all primary tumors of the liver and is the second most common benign tumor of the liver after haemangioma. The incidence of hepatocellular adenoma has increased since 1960 and is estimated to be approximately 0.05–5 per million a year. Hepatic adenoma is extremely rare and is associated with the use of oral contraceptives, most frequently in women between 20 and 40 years of age.
The clinical manifestations of benign hepatic tumors vary; they may be asymptomatic or may present by acute abdominal pain. Asymptomatic cases are usually detected incidentally during routine physical examinations or imaging studies.
The following imaging procedures can be used for the detection and differential diagnosis of benign hepatic lesions or tumors :( 1) sonography, (2) computed tomography, (3) scintigraphy, and (4) magnetic resonance imaging. These methods show clear differences in their ability to detect tumors of minimum size, in their sensitivity and specificity, and in the costs involved.
As for ultra sound , it has the following advantages: (1) it has a high diagnostic yield , (including extrahepatic areas), , (2) it is cost-effective, , (3) it can be used in various locations, , (4) it is not time consuming, and , (5) it does not burden the patient,(6) the use of new techniques , (contrast-enhanced power Doppler sonography, phase-invasion harmonic imaging) can help to make the assessment more reliable in individual cases. However US is clearly inferior to CT when it comes to diagnosing metastases, also the respective diagnostic reliability is highly dependent upon the investigator’s experience
As for CT, It has a greater sensitivity than sonography; however, there are higher costs involved, it takes more time, requires more space and entails exposure to radiation. More sophisticated methods such as helical CT or CT arterioportography allow a more differentiated application in certain constellations, (e. g. malignant lymphoma, metastases of parvicellular bronchial carcinoma, or breast cancer). Permanent-locationCT with administration of bolus contrast medium is suitable for the differentiation of haemangioma. Sonography and CT are considered to be useful complementary techniques in diagnosing hepatic focal lesions, since in this way foci can be detected which are missed by the respective other method.
MRI can be used for lesion characterization and as a problem-solving examination in cases in which the results from multidetector CT or ultrasonography examinations are inconclusive or incomplete. In other clinical situations, MRI can be used as the primary imaging modality providing a comprehensive examination of the hepatobiliary system. MRI is especially useful for the presurgical assessment of patients who are candidates for transplantation, surgical resection, or ablative treatments; it provides additional differentiation of unclarified findings, particularly in the diagnosis of haemangioma. Hypovascular lesions are detected more easily with SPIO-enhanced MRI, whereas detection and characterization of hypervascular lesions are improved with gadolinium-enhanced MRI.
Technetium- 99m, (99mtc) sulfur colloid scanningcan be indicated for differentiating an adenoma from FNH, (combination of colloid scintigram and hepatobiliary sequential scintigraphy) and for diagnosing haemangioma. Scintigraphy with labeled red blood cells is frequently used to differentiate cavernous haemangiomas from other lesions.
The use of biopsy in the diagnosis of hepatic lesions is controversial. It is accepted that the role of biopsy is to confirm benign pathology in patients with radiologically benign appearing lesions. For the majority of patients with FNA a benign biopsy result meant that they could be reassured regarding the absence of cancer, and safely observed.There is no indication for biopsy of a focal lesion in a cirrhotic liver when the patient is: (1) not a candidate for any form of therapy because of serious co-morbidity;(2) in case of decompensated cirrhosis and patient is on the waiting list for liver transplantation; and, (3) when the patient is a candidate for resection that can be performed with an acceptable morbidity and mortality risk. Every decision on biopsy of a focal liver lesion should be discussed by the multidisciplinary team, including a hepatobiliary surgeon.
It is accepted that unlike malignant liver tumors, the indication for resection of benign hepatic lesions, including haemangiomas, focal nodular hyperplasia, (FNH) and hepatocellular adenomas, (HCA) remains controversial. Because of the nature of benign liver tumors, clear indications are needed for partial liver resection, an operation associated with substantial postoperative morbidity and mortality. Indications for resection of benign liver masses include: (1) Severe or progressive symptoms, (2) Uncertain diagnosis with a suspicion for malignancy, and (3) Risk of hemorrhage or rupture.