LIVER TUMOURS
Liver tumours may be benign or malignant and malignant liver tumours may be primary (arising from liver) or secondary (metastatic).
Malignant tumours (cancers) comprise cells that have escaped from normal control of cell growth and development. Normal cell growth and development are tightly controlled and when cells reach the end of their normal life expectancy they are replaced by new cells. Malignant cells live longer than normal cells, divide and multiply more rapidly than normal cells and they acquire the ability to invade through membranes that normally separate different types of cells and hence into tiny lymph vessels and blood vessels. Once they invade lymph vessels and blood vessels cancer cells can disseminate through the body like seeds in the breeze. After cancer cells have travelled via the lymph or blood they can settle in distant organs, where they can "take root" and grow into new, secondary / metastatic tumours. In order for these metastases to establish themselves they have to develop their own blood vessels, which parasitise the blood vessels of the host organ. Cancer cells that disseminate may "take root" immediately or they may "lie dormant" for a variable period before developing when conditions are favourable or they may be destroyed by the immunological cells of the host. Secondary malignant tumours (metastases),therefore, develop in the liver after cancer cells have spread via the blood to the liver from a primary in some other organ e.g. colon.
Benign Liver Tumours:
The most common benign liver tumour, the cavernous haemangioma and the second most common, focal nodular hyperplasia are not, strictly speaking, neoplasms, because they do not comprise abnormally growing cells. They do however present as focal masses within the liver.
Cavernous Haemangiomas:
These are soft, spongy masses, which comprise abnormal blood vessels.
They are very common and almost always completely harmless.
In a small proportion of cases they become very large and might compress adjacent organs with resulting symptoms. Another very rare complication is the formation of clots within these abnormal blood vessels, which can result in abnormally high consumption of platelets and clotting factors. Only in these very uncommon scenarios would excision of these lesions be a consideration.
They often have a fairly typical (hyperechoic) appearance on U/S scans. Unfortunately, however, malignant tumours can also be hyperechoic and radiologists quite often incorrectly diagnose cavernous haemangiomas when the lesion is, in fact, a much more serious condition. Malignant lesions can usually be differentiated quite reliably by a skilled and experienced radiologist from a cavernous haemangioms with a 4-phase CT scan or MRI scan.
Focal Nodular Hyperplasia (FNH):
These are solid, firm, pale masses that typically have a central "scar". Size varies from less than a centimeter in diameter to huge lesions that may be many centimeters in diameter. They are usually solitary, but some patients have multiple lesions.
They comprise normal hepatocytes (liver cells) associated with abnormal bile ducts and blood vessels and without the normal lobular architectural arrangement of the cells.
If one can confidently make a diagnosis of FNH, as one can usually do with the aid of MRI scans done with hepatocyte-specific contrast medium (Primavist) administered intravenously during the scan, the patient can be reassured that the mass is harmless and not prone to cause complications. However, if one cannot exclude the lesion being a well-differentiated hepatocellular carcinoma or hepatic adenoma or if the patient is experiencing significant symptoms that can be attributed to the lesion, it may be advisable / justifiable to remove it.
Malignant Liver Tumours - Primary
The presence of cirrhosis and the stage of fibrosis are important factors in deciding therapeutic options and predicting prognosis, especially in cases of liver tumor resection. However, it is sometimes difficult to use conventional measurements to diagnose well-compensated cirrhosis.
Biochemical markers of liver cirrhosis can be measured and liver stiffness can be measured by Fibroscan®.
The behaviour of the microbubbles in sonographic contrast medium in the portal vein may reflect hemodynamic changes due to hepatic fibrosis. Preoperative Sonazoid™ contrast-enhanced ultrasonography (US) performed to measure the slope gradient of the hepatic artery, portal vein and hepatic veins, the hepatic vein arrival time and intrahepatic circulatory time. The portal vein slope gradient is considered to reflect the hemodynamic changes of cirrhosis and is helpful as a noninvasive diagnostic modality for compensated liver cirrhosis.
Anatomical segmentectomy rather than non-anatomical resection, should be the first choice of surgical procedure for HCC, if liver function permits.
