Unless a piece of normal liver is being removed for transplantation, the indications for resection of the liver revolve around the presence of an abnormality in the hepatic parenchyma or bile ducts, which can and should be removed. Neoplasms are removed either because they are or could be malignant, or because they are causing symptoms that will be improved by hepatectomy. Other lesions, such as abscesses, are removed because specific circumstances suggest that resection, rather than drainage, is the least morbid treatment. Often, the circumstances in which resection is chosen over drainage for these patients involve anatomic abnormalities such as localized biliary strictures that have provoked the infectious problem. Intrahepatic biliary strictures may be caused by devascularizing events such as previous surgery or following trauma. They can also occur as a result of several other problems such as stones, or Caroli's disease, or even parasitic infections like Clonorchis (Oriental Cholangiohepatitis). Occasionally, a piece of devitalized liver is resected along anatomic planes as a posttraumatic debridement or to control bleeding.
The most common reason tumors are removed from the liver is to attempt a cure for a patient with a malignant neoplasm. Primary hepatocellular cancer, or hepatoma, is the most common malignant solid tumor worldwide. However, it is much less common in the United States. Here, the most common malignant neoplasms of the liver are metastatic deposits from lung, breast, and gastrointestinal (GI) primary sites. Some of these patients can be cured by removing the metastases from the liver. However, they are a highly selected group who have a small number of isolated colorectal or neuroendocrine metastases in the liver. Patients with metastatic lung, pancreatic, breast or gastric cancer are not reliably salvaged by resectional or ablative strategies for the liver metastases. Similarly, a minority of patients with hepatoma can be cured by resection and/or ablation because these tumors tend to present at a late stage or in a cirrhotic liver that will not tolerate a resection. Nevertheless, there is no other curative treatment for these cancers and so if resection or ablation is feasible, it should be undertaken.
For both primary hepatocellular cancer and metastatic colorectal cancer, there is currently no demonstrable benefit to "debulking" the cancer. Consequently, operative resection or ablation should be undertaken only if a complete resection with clear margins can be contemplated by preoperative review of the scans. The key to technical success within the liver is a clear margin on the target tumor and it does not matter whether these are achieved by anatomic or nonanatomic resections or ablations. These basic principles are valid for a number of other more uncommon cancers such as peripheral cholangiocarcinomas and sarcomas. The major exception is when the tumor is hormonally active as happens with some neuroendocrine cancers. In these cases resectional or ablative maneuvers that only debulk the patient can have a significant palliative impact and should be contemplated despite expectations that the disease will recur locally.
Benign tumors are removed when there is doubt about their benign nature as may happen with any tumor, but particularly with hemangiomas, which should not be biopsied because of the possibility of precipitating uncontrolled bleeding, and hepatocellular adenomas, which may be confused with well differentiated hepatoma. They are also removed when they threaten other complications such as hemorrhage. Interestingly, the threat of spontaneous rupture and bleeding is from adenomas, not hemangiomas as was commonly feared (7,8). Finally, benign tumors are removed when they cause symptoms such as pain, or symptoms consistent with a mass effect (satiety, breathlessness, distention, and so on), or rare systemic problems such as the consumptive coagulopathy that can occur with giant hemangiomas. Cysts are operated on for the same sorts of reasons: doubt about their benign nature (e.g., complex cysts) or because they are symptomatic. In the latter case, the operation performed is a fenestration; the top of the cyst is excised to allow it to drain freely into the peritoneal cavity.
A major hepatic resection is sometimes required to remove cholangiocarcinomas of the proximal bile duct. These tumors, which frequently involve the bifurcation of bile ducts, are also known as Klatskin's tumors. The cancer often extends proximally and distally along the bile ducts so that achieving a clear luminal margin, particularly on the hepatic side, with a segmental resection of the bile duct can be problematic. The solution is to take the liver as well as the bile duct. Achieving clear radial margins can also be a problem because the bile ducts run as one component of a "cable" made up of the portal veins and hepatic arteries (Fig. 4). Consequently, achieving a clear radial margin may involve the sacrifice of these vascular structures and the hepatic parenchyma they subtend.
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