Fascioliasis is a zoonotic disease caused by the trematode F. hepatica. The prevalence of this parasite is high in North Africa, Western Europe, and South America, especially in the Andes of Peru and Bolivia. In Peru, the prevalence of this parasite ranges between 8% and 36%.7,8
The infection begins with the ingestion of food or water contaminated by Fasciola metacercariae, which then migrate through the stomach and duodenum. The excysted form of the parasite penetrates the intestinal wall, gaining access to the peritoneum where it adopts an inactive form for several days before migrating to the liver. This acute phase lasts 3–5 months and is characterized by fever, abdominal pain, hepatomegaly, and eosinophilia.2,9 In the chronic phase, the parasite reaches the biliary tree where it can cause biliary colic and cholangitis. Rarely, larvae can migrate to ectopic locations such as the brain, epididymis, and stomach.1,9 Previously, Acosta-Ferreira et al described 2 patients with gastric involvement due to Fasciola. In both cases, peptic ulcer-like lesions were found in the stomach with no evidence of overt mass.10
A high index of suspicion is important to diagnose fascioliasis. Patients may present with nonlocalized abdominal pain, eosinophilia, and characteristic abdominal CT findings. However, the diagnosis requires demonstrating parasites or eggs in feces, biliary samples, or duodenal aspirates.11,12 Although stool studies have been shown to have high sensitivities in the chronic phase of infection, they may fail to detect Fasciola during the early stages.1,11 Therefore, serologic studies may play a more prominent role in the diagnosis of both acute and chronic disease. For example, enzyme-linked immunosorbent assay (ELISA) is able to achieve high sensitivity (96.7%) and specificity (91.2%) in the diagnosis of this infection.11,13 For this case, IgG immunoblot was used as a surrogate for ELISA because of a lack of ELISA availability in tertiary care centers while still achieving satisfactory sensitivity (71%–96%) and specificity (88%–100%).11,14
Abdominal ultrasonography is of little value during the acute phase because biliary dilation and tortuousness of the bile ducts appears approximately 12 weeks after the onset of infection.1 Instead, contrast-enhanced CT scan can be useful in up to 90% of cases because it can demonstrate the presence of multiple, clustered hypodense lesions which tend to converge toward the hepatic hilum.13,15 Endoscopy with cholangiopancreatography may be useful to detect bile duct abnormalities seen in chronic infection. Furthermore, they may play a role in the management of biliary obstruction.16,17 Little is known about the use of endoscopic ultrasonography in cases of Fasciola in the gastrointestinal tract. However, it is possible that nonspecific cystic structures in the submucosal layer of the stomach are associated with Fasciola-induced pseudotumor. On histopathology, most findings reported in the literature are nonspecific such as granulomas and Charcot-Leyden crystals surrounded by an eosinophilic infiltrate.16,18 However, eggs have been found in specimens from the liver, biliary system, and bowels.9,19 In this patient, biopsy samples revealed multiple fragments of this parasite and ovoid formations covered by an eosinophilic spiny cuticle (Figure 4).
The patient was treated with triclabendazole 10 mg/kg for 2 days, which has been associated with the elimination of immature and mature forms of the parasite.18,19 On follow-up, the patient's positive response to therapy was reflected in his weight gain and increased oral intake. Repeat laboratory studies demonstrated resolution of eosinophilia, decreased antibody titers, and negative fecal studies. Repeat abdominal CT showed a benign focal lesion in the minor curvature of the stomach in line with benign disease sequela.16
Diagnosis of F. hepatica is challenging. Although abdominal pain and jaundice are prominent signs of chronic stages, unspecific symptoms, weight loss, eosinophilia, and endoscopic findings could be initial diagnostic clues. Routine screening with a primary provider can be considered, especially in endemic areas. This is a novel case of F. hepatica presenting as a gastric pseudotumor.
Author contributions: L. Calixto-Aguilar wrote the manuscript. L. Calixto-Aguilar and G. Vasquez-Rios reviewed the literature. G. Vasquez-Rios, J. Contreras-Grande, W. Ramos-Castillo, and E. Guzmán-Calderón edited the manuscript. E. Guzmán-Calderón is the article guarantor.
Financial disclosures: None to report.
Informed consent was obtained for this case report.
Previous presentation: This case was presented in part at ACG Annual Scientific Meeting; October 5-10, 2018; Philadelphia, Pennsylvania.
The authors express their gratitude to the medical personnel at Hospital Nacional Edgardo Rebagliati Martins and Tropical Medicine Institute “Alexander von Humboldt” for their technical support. Furthermore, they would like to thank Dr Neil Evans and Dr Christian Caceres from the Department of Internal Medicine at Saint Louis University School of Medicine for their valuable criticism to this manuscript.
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© 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The American College of Gastroenterology.
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