Echinococcal hepatic lesion mimicking metastasis from colon cancer: two case reports.

BACKGROUND: Echinococcus is a worldwide zoonosis, primarily causing liver lesions. Accidentally detected, these lesions enter the differential diagnosis of a tumor, including metastasis. This situation is especially challenging in patients with colorectal cancer, as both diseases affect mainly the liver. CASE PRESENTATION: We report two patients with a newly diagnosed colorectal cancer. Pre- and intraoperatively radiological imaging revealed hepatic lesions which were resected on suspicion of colorectal cancer metastasis. Histology showed granulomatous lesions with characteristic parasitic membrane consistent with an echinococcal cyst. The diagnosis was confirmed by specific polymerase chain reaction. CONCLUSIONS: Focal hypoechoic liver lesion in patients with colorectal cancer should be primarily considered as a liver metastasis and resected whenever feasible. Other uncommon etiologies, including parasitic lesion as echinococcal cysts, should be taken in consideration, as this could lead to major changes of the management and prognosis of the affected patients.

Radiofrequency ablation of liver tumors: Actual limitations and potential solutions in the future.

Over the past decade, radiofrequency ablation (RFA) has evolved into an important therapeutical tool for the treatment of non resectable primary and secondary liver tumors. The clinical benefit of RFA is represented in several clinical studies. They underline the safety and feasibility of this new and modern concept in treating liver tumors. RFA has proven its clinical impact not only in hepatocellular carcinoma (HCC) but also in metastatic disease such as colorectal cancer (CRC). Due to the increasing number of HCC and CRC, RFA might play an even more important role in the future. Therefore, the refinement of RFA technology is as important as the evaluation of data of prospective randomized trials that will help define guidelines for good clinical practice in RFA application in the future. The combination of hepatic resection and RFA extends the feasibility of open surgical procedures in patients with extensive tumors. Adverse effects of RFA such as biliary tract damage, liver failure and local recurrence remain an important task today but overall the long term results of RFA application in treating liver tumors are promising. Incomplete ablation of liver tumors due to insufficient technology of ablation needles, tissue cooling by the neighbouring blood vessels, large tumor masses and ablation of tumors in close vicinity to heat sensitive organs remain difficult tasks for RFA. Future solutions to overcome these limitations of RFA will include refinement of ultrasonographic guidance (accuracy of probe placement), improvements in needle technology (e.g. needles preventing charring) and intraductal cooling techniques.

Radiofrequency ablation of liver tumors: a novel needle perfusion technique enhances efficiency.

OBJECTIVE: We hypothesize that perfusion of an expandable radiofrequency ablation (RFA) needle with saline solution might help prevent charring and increase efficiency. SUMMARY BACKGROUND DATA: RFA has become an important adjunct to modern liver surgery. However, ablation is time-consuming and hazardous due to charring around the radiofrequency electrodes. METHODS: From June 2000 to November 2004, 159 liver tumors with a median diameter of 2.0 cm were treated with RFA, 54 tumors of them according to the manufacturer's standard protocol and 105 tumors according to the novel perfusion protocol. No randomization was applied. All patients were followed up with contrast enhanced computed tomography (CT) at regular intervals. Local recurrence was defined as radiologic and/or histologic evidence of viable tumor within or at the ablated liver area. RESULTS: Both study groups were comparable with regard to tumor characteristics, procedure related complications, and median times of follow-up (27 mo in the standard group versus 23 mo in the perfusion group). The median RFA time was significantly reduced from 18.9 min in the standard group to 8.0 min in the perfusion group. The rates of incomplete ablations were comparable in both groups (3.7% versus 2.8%). The rate of local recurrences at the RFA site was 6.9% overall, 11.1% in the standard group, and 4.8% in the perfusion group. No tumor seeding along the puncture channel was observed. CONCLUSIONS: The perfusion of an expandable RFA needle with saline solution significantly accelerates the ablation procedure of liver tumors without increase of complications and without compromising the oncosurgical result.