A 35-year-old female patient who underwent right hemicolectomy for cecal cancer was referred to our Liver Transplant Institute for surgical treatment of colon cancer liver metastasis.
Patient stated that she had been eating watercress for a long time.
History of past illness
The patient stated that she underwent colonoscopy at another clinic because of exhaustion, fatigue, and anemia, and right hemicolectomy was performed upon detection of a cecal tumor on colonoscopy. Histopathological examination revealed cecal adenocarcinoma with subserosal fat tissue invasion and five metastatic lymph nodes in 32 lymph nodes. Preoperative contrast-enhanced abdominal computed tomography (CT) revealed hypodense and heterogenous lesions with soft tissue density that were 40 mm x 33 mm in diameter in the right lobe of the liver (Figure 1). At the 3rd postoperative week, multiple hypermetabolic lesions with SUVmax of 5.3 in segments V, VII, and VIII of the liver were detected on performing 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG-PET/CT) after 5.5 mCi 18F-FDG injection (Figure 2). In addition, hypermetabolic lesions were detected in the subhepatic (SUVmax: 7.1), superior mesenteric (SUVmax: 7.1), and aortocaval window (SUVmax: 7.3). Six cycles of adjuvant FOLFOX (folinic acid, fluorouracil, oxaliplatin) and bevacizumab were administered to the patient. In control 18F-FDG-PET/CT, the SUVmax values of liver lesions decreased to 3.8, and the SUVmax values of the lymph nodes did not regress. Thus, the same chemotherapy regimen was continued, and control 18F-FDG-PET/CT was performed at the end of 12th che-motherapy course. In the last 18F-FDG-PET/CT, all previously seen lesions were stable, whereas they regressed significantly both dimensionally and metabolically. Subsequently, the patient was referred to our center. Dynamic liver magnetic resonance imaging (MRI) performed immediately after the 12th chemotherapy course showed regression of the lesions in the liver. After 6 weeks, dynamic MRI at our center revealed that the lesions were more prominent than those on previous magnetic resonance images. Because the patient had colon cancer, the lesions in the liver were hypermetabolic in 18F-FDG-PET/CT, and the lesions started to regrow after chemotherapy, and the patient planned to undergo surgery. Right hepatectomy was performed to include all lesions with intraoperative ultrasonography. In addition, all lymph nodes in the hepatoduodenal ligament, celiac, and aortocaval window were resected, and a frozen section was sent for analysis, and no tumor was detected in the lymph nodes. In the histopathological examination of the hepatectomy specimen, the lesions had granulomatous foci on a tract, characterized by suppuration enriched with eosinophils (Figure 3-4), which was noted to be compatible with F. hepatica infection by a pathologist. Based on this result, preoperative blood tests of the patient were reexamined, and eosinophil count was 0.78 × 109/L (normal range: 0–0.5). F. hepatica IgG enzyme-linked immunosorbent assay (ELISA) (Synlab MVZ Leinfelden GmbH, Leinfelden-Echterdingen, Germany) was positive.
Figure 1 Computed tomography image after contrast medium injection.
Axial computed tomography image revealed that hypodense and heterogenous lesions with soft tissue density of maximally 40 mm × 33 mm in diameter in the right lobe of the liver.
Figure 2 18F-fluorodeoxyglucose positron emission tomography/Computed tomography was performed using 5.
5 mCi of 18F-fluorodeoxyglucose injection. Maximum intensity projection of images shows that high fluorodeoxyglucose uptakes in different segments of the liver.
Figure 3 Granuloma with central necrosis (HE ×100).
Figure 4 Charcot–Leyden crystals near granuloma (arrows) (HE ×100).
Two phases in the life cycle of F. hepatica have been defined: acute (hepatic) and chronic (biliary). The phase where the parasite penetrates through the liver capsule and invades the liver parenchyma is the hepatic phase. In this phase, parasites digest hepatocytes, open tunnels in the parenchyma, and remain in the parenchyma for months[2,4]. Signs and symptoms in the hepatic phase commonly mimic those of liver abscess[2,5]. Patients in this phase usually experience non-specific symptoms, such as loss of appetite, weight loss, right upper quadrant pain, fever, sweating, urticaria, and arthralgia. Hepatomegaly, right upper quadrant pain, and prominent eosinophilia can be seen[4,5]. The phase where the parasite becomes visible in the bile ducts is the biliary phase. In this phase, signs and symptoms, such as biliary colic, epigastric pain, and jaundice, which are related to biliary tract obstruction, develop. The level of cholestatic enzymes and bilirubin may increase. Symptoms of acute pancreatitis may develop in patients with distal bile duct obstruction.
The following diagnostic modalities are used in the diagnosis of fascioliasis: clinical suspicion, parasite eggs observed by direct microscopy (stool, bile, or duodenal aspirate), detection of DNA of the parasite with real-time polymerase chain reaction (stool, bile or duodenal aspirate), serological tests (immunoelectrophoresis, counter-immunoelectrophoresis, metacercarial precipitin test, indirect hemagglutination), complement fixation, immunofluorescence assay, radioimmunoassays, enzyme-linked immunofiltration assay (ELIFA), enzyme-linked immuno-electrotransfer blot (EITB) or western blot, Falcon assay screening test–ELISA (FAST-ELISA), micro-ELISA, dot-ELISA], radiological examination of lesions of the liver parenchyma and biliary ducts (CT, MRI, MRCP, and 18F-FDG-PET/CT), endoscopic examination of parasite directly (ERCP, endo-ultrasonography) and histopathological examination of the parasite on tissue biopsy[3,9,10].
Appearance of parasite eggs in the stool has a diagnostic value only in the biliary phase[5,9]. Eosinophilia and anemia may be seen in biochemical tests[3,11]. ELISA is the leading serological test with high sensitivity and rapid results. However, it should be supported by radiological findings due to its high false positive and negative rates. Appearance of tunnel-like linear and branched hypodense lesions on CT is characteristic. In most patients, iso-hyperintense (T2) and iso-hypointense (T1) lesions can be seen on MR and MRCP images, and these lesions can mimic malignant diseases of the biliary tract. ERCP and endoscopic ultrasonography are very useful in the biliary phase[9,11]. Similar to this case, ERCP is the most appropriate treatment modality both to remove parasites from the bile ducts and to decompress the bile ducts.
Diagnosis, staging, response to treatment, and recurrence of malignant diseases can be determined successfully by 18F-FDG-PET/CT. However, false-positive results can be obtained in inflammations due to radiotherapy and surgery or in various chronic infections. These can sometimes mimic malignancy[13-15]. Similar to this case, carefully evaluating high FDG uptake in PET/CT is particularly important in a patient with malignancy. Otherwise, because patients can only be cured with anti-helminthic treatment, they may undergo unnecessary major surgical procedures or che-motherapy.
The most common diseases confused with fascioliasis are viral hepatitis, liver abscess, cholecystitis, sclerosing cholangitis, AIDS-associated cholangitis, ruptured hydatid cyst, and ascariasis, clonorchiasis, and primary and metastatic tumors of the liver and biliary tract[2,5,9]. Therefore, misinterpretation of these signs and symptoms in areas where fascioliasis is not endemic is possible, and thus, diagnosis may be delayed. Similar to this case, in a patient with colon cancer, it is expected that liver lesions will be interpreted as a tumor by a radiologist or nuclear medicine specialist without experience in fascioliasis.
The first and best option for the treatment of fascioliasis is triclabendazole, and another alternative drug is nitazoxanide. Triclabendazole is used in two doses (10 mg/kg/dose) 24 h apart and is effective at all stages regardless of the phase of the disease. Nitazoxanide is a good alternative to triclabendazole, and it is administered as 500 mg twice daily for 7 d. Other drugs that were used previously and are no longer recommended due to drug resistance or toxicity, including bithionol, praziquantel, emetine, dehydroemetine, metronidazole, albendazole, niclofolan, and chloroquine. In this case, we had to administer it twice in a few months.