Complete Resolution of an Alveolar Echinococcosis Liver LesionFollowing Percutaneous Treatment

Mert Koroglu,1 Okan Akhan,2 Mustafa Tekinalp Gelen,3 Banu Kale Koroglu,4 Harun Yildiz,1

Gonul Kerman,1 Orhan Oyar1

1Department of Radiology, Faculty of Medicine, Suleyman Demirel University, Isparta, Turkey2Department of Radiology, Faculty of Medicine, Hacettepe University, Ankara, Turkey3Department of Pathology, Faculty of Medicine, Akdeniz University, Antalya, Turkey4Department of Internal Medicine, Faculty of Medicine, Suleyman Demirel University, Isparta, Turkey

Abstract

Herein we present a 63-year-old male patient with a solid hepaticalveolar echinococcosis diagnosed by surgical biopsy. His liverlesion, which was infected, was drained by percutaneous cathe-terization. The lesion surprisingly disappeared completely after thetreatment. The patient was followed-up without any symptoms for20 months after the drainage. As alveolar echinococcosis of theliver behaves like a slow-growing liver cancer, the disappearanceof our patient�s lesion was a very unusual and rare outcome, which,to the best of our knowledge, has never been published in theliterature.

Key words: Liver—Echinococcus multilocularis—Echinococco-sis—Abscess—Ultrasonography—Spiral computed tomography—Interventional radiology—Benzimidazoles

Alveolar echinococcosis is a rare parasitic disease that is caused byEchinococcus multilocularis. This parasite causes various types ofhepatic lesion. In contrast to Echinococcus granulosus, imagingcharacteristics and treatment options of the alveolar echinococcosishave not been fully established [1]. The purpose of this article is tohighlight the atypical imaging findings, clinical course, and treat-ment options of alveolar echinococcosis.

Case ReportA 63-year-old male patient was admitted to the hospital due to anabdominal mass. His past medical history was unremarkable. Physicalexamination revealed hepatomegaly and a suspicious mass in the epigas-trium. An increase in the liver enzymes was detected. Abdominal ultra-sound (US) examination revealed a solid hyperechoic 8 · 8 · 9-cm mass inthe liver (Fig. 1). The patient was operated on, but the mass was found to beinoperable and only an intraoperative core biopsy was performed. Patho-logical examination revealed the diagnosis of alveolar echinococcosis(Fig. 2).

The patient has been receiving continuous albendazole treatment at adosage of 20 mg/kg/day for 2 years. During a follow-up US examination 22months after the operation, a 2-cm-thick hypoechoic collection around thesolid mass was detected (Fig. 3). Abdominal computed tomography (CT)

examination confirmed the hypoechoic collection around the solid lesion(Fig. 4). The lesion was surrounding the inferior vena cava and portal vein.Focal liver calcifications were also detected on the CT examination. At thattime, the patient did not have any symptoms or signs of infection and wasmonitored more closely; 4 months later, he developed nausea, vomiting,jaundice, and fever. He was readmitted and abdominal CT examination hadshown that the hypoechoic collection increased in size. A collection nearly2–3 cm thick was found around the solid part of the lesion. The density ofthe solid part of the lesion had also decreased, suggesting necrosis. Bileducts anterior to the lesion were shown to be dilated (Fig. 5). The patientwas informed about percutaneous treatment, its alternatives, and potentialrisks. A third-generation cephalosporin was used for the purpose of pro-phylaxis. The procedure was performed under US and fluoroscopic guid-ance. The collection was punctured with an 18G Seldinger needle under USguidance. Purulent material was aspirated and contrast material was in-jected into the cavity (Fig. 6). Percutaneous puncture, aspiration, and theintroduction of the contrast agent confirmed the presence of an abscesscavity and a connection between the cavity and bile ducts. A 0.035-in. J tipguidewire (Amplatz Super Stiff Guidewire; Boston Scientific, USA) wasinserted through the Seldinger needle, followed by a 10F pigtail drainagecatheter (Flexima Regular All Purpose Drainage Catheter Set; BostonScientific, USA). This procedure was performed in an over-the-wire ap-proach in a single session. Streptococcus intermedius was cultured andfound to be the pathogen agent. Intravenously, 1 g meropenem wasadministered three times a day for 23 days. Drainage through the catheterwas found to contain bile. Endoscopic sphincterotomy was performed. CTexamination on the seventh day of the catheterization showed the catheterand a decrease in the size of the lesion (Fig. 7). Fever subsided on theeighth day of catheterization. Daily drainage was decreased to 10 mL andthe catheter was withdrawn 20 days after the catheterization. The patientwas followed-up with abdominal US and CT. Twenty months later, thelesion had completely disappeared on CT (Fig. 8), accompanied by relief ofsymptoms and the liver function tests and bilirubin values were all normal.

DiscussionHepatic alveolar echinococcosis is a serious life-threatening dis-ease with a high mortality rate and poor prognosis in the absence ofvigilant clinical management. This disease develops followinghuman infestation by the larvae of Echinococcus alveolaris. Thefox is the most common host of the adult parasite, with dogs or catsbeing less frequently cited hosts. The fox disseminates the parasiticeggs within feces, contaminating vegetation. Intermediate hosts,most commonly wild rodents (usually microtine and arvicolid ro-dents), are infected through the consumption of contaminated wildCorrespondence to: Mert Koroglu; email: mertkoroglu@hotmail.com

ª Springer Science+Business Media, Inc. 2006

Published Online: 6 October 2005CardioVascularand InterventionalRadiology

Cardiovasc Intervent Radiol (2006) 29:473–478

DOI: 10.1007/s00270-005-0017-0

berries. The fox is contaminated by the consumption of infestedrodents. Human contamination occurs by the intake of contami-nated wild berries or water and by direct contact with foxes [2–4].

Echinococcus multilocularis has recently been discovered tohave a much wider geographical distribution than was previouslythought and there is clear evidence that the parasite can readilyspread from endemic to nonendemic areas [3, 5]. The main en-demic regions for alveolar echinococcosis are central Europe,Russia, Turkey, Japan (Hokkaido), the Kurile Islands, China, andNorth America [6].Although this taenia is similar to that of Echinococcus

granulosus, which causes hydatid cysts of the liver, these twodiseases are completely different in terms of histopathologicalprocess. In contrast to Echinococcus granulosus, Echinococcusmultilocularis larvae grow indefinitely; they produce liver necrosisand induce a prominent granulomatous reaction and the lesions arenever limited by a fibrous shell.

Echinococcus multilocularis produces multilocular alveolarcysts (1–10 mm in diameter) that resemble alveoli and grow bymeans of exogenous proliferation with cysts that progressivelyinvade the host tissue by means of peripheral extension of theprocesses originating in the germinal layer. The larvae causeinvasive and destructive changes in the tissue [1, 7]. This area isseparated from the hepatic parenchyma by inflammatory cells [8].Alveolar echinococcosis of the liver behaves like a slow-

growing liver cancer. Invasion of the bile ducts and the vessels andnecrosis in the central part of the parasitic tissue lead to very severecomplications, such as cholangitis, liver abscesses, septic shock,portal hypertension, biliary cirrhosis, and Budd–Chiari syndrome,which can seriously affect not only the quality of life of infectedpatients but also their survival. In fact, the disease is always fatalunless it is identified in a timely fashion and completely removedby partial hepatectomy [6].Alveolar echinococcosis typically presents later than the cystic

form. Cases of alveolar echinococcosis are characterized by aninitial asymptomatic incubation period of 5–15 years and a sub-sequent chronic course. Early clinical symptoms are lacking andmost cases are diagnosed at late stages with unresectable hepaticlesions.

Although the liver is the most frequently involved organ,hematogenous dissemination to other organs can also occur. Theright lobe is involved most frequently, with involvement of theporta hepatis or multiple lobes less frequently. Parasitic lesionsin the liver can vary from small foci a few millimeters in size tolarge (15–20 cm in diameter) areas of infiltration. Extrahepaticprimary disease is very rare (1% of cases). Thrteen percent ofcases present as multiorgan disease. One-third of cases presentwith cholestatic jaundice, one-third present with epigastric pain,and the remaining third present with vague symptoms likeweight loss or fatigue or are diagnosed incidentally duringradiological examinations [3].In endemic areas, alveolar echinococcosis is a challenge in the

diagnosis of liver masses [9, 10]. In many cases, the primarydiagnosis is established by immunological studies [2, 3]. However,US and CT have been used to localize and determine the extent ofdisease [11, 12]. The most frequent morphological profile ofalveolar echinococcosis is an intrahepatic heterogeneous, infiltra-tive, and destructive mass, with irregular outlines and an avascular

Fig. 1. Preoperative US examination revealed the

8 · 8 · 9-cm hyperechoic mass in the liver.

Fig. 2. Alveolar echinococcosis. Membranes were seen in biopsymaterial (arrows). Hematoxylin and eosin stain; magnification: ·20.

474 M. Koroglu et al.: Pecutaneous Treatment of Alveolar Echinococcosis Liver Lesion

and necrotic center that appears on US as a hypoechoic lesion witha hyperechoic rim.Reported CT findings of liver infestation by Echinococcus

multilocularis include heterogeneous hypodense areas with lackof contrast enhancement, pseudocystic necrotic areas, charac-teristic calcifications, and dilatation of the intrahepatic bile ducts[1, 8, 11, 13].

Hepatic lesions caused by alveolar echinococcosis consist ofcystic and solid components. Small round cysts on magnetic res-onance imaging (MRI) correspond to metacestodal vesicles,whereas large and irregular cystic lesions are consistent with liq-uefaction necrosis [1]. Kodama et al. have classified the MRIfindings of liver alveolar echinococcosis. Type 1 lesions arecharacterized by multiple small round cysts without a solid com-

Fig. 3. Follow-up US examination 22 months afterthe operation revealed 2-cm-thick hypoechoic

collection around the solid mass (arrows).

Fig. 4. Abdominal CT examinationconfirmed the collection around the solid

lesion. Localization and extent of the lesion

was determined. Invasion to the inferior

vena cava (arrowhead) and portal vein wasdemonstrated. Additionally, two calcified

liver lesions were detected (arrows).

M. Koroglu et al.: Pecutaneous Treatment of Alveolar Echinococcosis Liver Lesion 475

Fig. 5. Abdominal CT examination 4

months after the previous CT demonstrated

the increase in thickness of the collection.Note the decrease in the density of the solid

part of the lesion, suggestive of necrosis.

Bile ducts anterior to the lesion are dilated(arrows).

Fig. 6. Direct roentgenograms during the

percutaneous treatment demonstratedabscess cavity and bile ducts (arrows) filled

with contrast material.

476 M. Koroglu et al.: Pecutaneous Treatment of Alveolar Echinococcosis Liver Lesion

ponent. Type 2 includes multiple small round cysts with a solidcomponent. Type 3 represents a lesion with a solid componentsurrounding large and/or irregular cysts with multiple small roundcysts. Type 4 is a solid lesion without cysts. Type 5 is a large cystwithout a solid component [1].

Calcifications are common in hepatic alveolar echinococcosislesions [8]. Because of the high detectability of calcifications withCT, MRI and CT are complementary imaging techniques that al-low precise depiction of alveolar echinococcal lesions [1]. MRI issuperior in evaluating the extension of parasitic lesions to vascular

Fig. 7. CT examination on the seventhday of the catheterization showed the

catheter and a decrease in the size of the

lesion.

Fig. 8. CT examination 20 months afterthe catheterization showed that the lesion

had completely disappeared.

M. Koroglu et al.: Pecutaneous Treatment of Alveolar Echinococcosis Liver Lesion 477

structures or transdiaphragmatic or retrohepatic extensions [9]. CTis superior in the detection of the calcifications.Differential diagnoses of alveolar echinococcosis include sev-

eral hepatic tumors such as cystadenoma, cystadenocarcinoma,peripheral cholangiocarcinoma, and metastasis. These tumors canbe differentiated from alveolar echinococcosis because they areusually enhanced and rarely calcified [1]. Lack of enhancement is acharacteristic feature of alveolar echinococcosis lesions and mightaid in the differential diagnosis of hepatic lesions [2, 8]. Earlydiagnosis and precise localization is essential for radical surgery.Radical surgery has been the mainstay of therapy, but sometimes itis impossible to perform radical surgery, as in our case [1, 14].Surgical resection of the primary lesion has offered the only provencurative treatment for patients with alveolar echinococcosis of theliver. However, resection is often difficult in patients with exten-sive local or disseminated disease or in patients for whom surgeryis contraindicated [15]. Complete resection of the lesions could notbe performed in 38.7% of the patients in one series [16]. Recur-rence of the lesion occurs even after apparently curative operations.Cases of late diagnosis require lifelong pharmacological treat-

ment with benzimidazoles and thorough follow-up, becausebenzimidazoles are assumed to exert only a parasitostatic effect onEchinococcus multilocularis [8, 15]. Albendazole is a broad-spectrum anthelmintic agent. Albendazole is apparently absorbedto a greater extent than other benzimidazoles and is convertedalmost completely to the metabolite albendazole sulfoxide, whichis an effective agent against protoscoleces. Due to the highrecurrence rate caused by treatment interruption, discontinuation ofbenzimidazoles in alveolar echinococcosis with persisting liverlesions is discouraged [15]. Perioperative treatment with albenda-zole can decrease the recurrence rate and increase the success rateof the operation [16–19].Management of the septic complications of alveolar echinococ-

cosis of the liver, such as cholangitis or liver abscesses, should pri-oritize interventional radiology [20]. A liver abscess in our patientwas treated by percutaneous catheterization, which led to completedisappearance of the hepatic alveolar echinococcus lesion.Treatment of portal hypertension in alveolar echinococcosis of

the liver is also problematic. In patients without cirrhosis, percu-taneous stent placement in the hepatic veins represents a promisingtreatment alternative [21].It might seem quite surprising, but liver transplantation and

lifelong immunosuppressive therapy has been proposed and used inadvanced cases since 1985 [20]. Liver transplantation should onlybe considered in patients with very severe hilar extension, leadingto uncontrolled biliary infections, symptomatic secondary biliarycirrhosis with ascites, and/or severe variceal bleeding owing toportal hypertension. Fortunately, this kind of patient is becomingrarer as a result of the trend toward earlier diagnosis of the disease.In fact, during the past 10 years, the extensive use of abdominal USand serological screenings in endemic areas has resulted in an

increase in the discovery of smaller alveolar echinococcosis le-sions, which are curable with limited surgery [2, 8].In conclusion, the disappearance of the hepatic alveolar echi-

nococcosis lesion by percutaneous drainage was an excellent re-sult, which, to the best of our knowledge, has not been previouslypublished in the literature.

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