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Pathology of pyogenic liver abscess in children
F E Pereira1, C Musso, J S Castelo
1Department of Pathology, Núcleo de Doenças Infecciosas CBM-UFES, Av Marechal Campos 1468, 29040-091 Vitória, ES Brazil.
Insights
Nematode infections may predispose children to pyogenic liver abscesses (PLA). Evidence suggests migrating larvae cause liver granulomas, increasing PLA risk in pediatric patients, especially in regions with high helminthic infection rates.
Area of Science:
- Pediatric Pathology
- Infectious Diseases
- Hepatology
Background:
- Pyogenic liver abscess (PLA) in children often lacks identified predisposing factors.
- PLA in Brazil is frequently linked to helminthic infections and eosinophilia.
- Nematode larval migration through the liver may induce immunomodulation and bacterial trapping.
Purpose of the Study:
- To investigate preexisting liver lesions in pediatric PLA cases.
- To explore the hypothesis that nematode larval migration predisposes children to PLA.
Main Methods:
- Autopsy (16) and surgical biopsy (6) samples from 22 pediatric PLA cases were analyzed.
- Histopathological examination identified pyogenic inflammation, granulomas, and nematode-related findings.
- Immunohistochemistry was used to detect nematode antigens and larval fragments.
Main Results:
- Six cases exhibited granulomas resembling larva migrans visceralis, with nematode antigens and larval fragments detected.
- Numerous eosinophils and Charcot-Leyden crystals were present in abscesses and portal triads.
- Bile duct ascariasis was observed in four cases, with eggs found in surrounding liver parenchyma in two.
Conclusions:
- The presence of nematode-induced granulomas supports the hypothesis that helminth larval migration is a predisposing factor for pediatric PLA.
- Findings highlight the role of helminthic infections in the pathogenesis of pediatric pyogenic liver abscesses.
- Further research is warranted to elucidate the immunomodulatory mechanisms involved.
Abstract:
Little is known about preexisting lesions in livers of children with pyogenic liver abscess (PLA). Study of these lesions may elucidate possible predisposing factors for the disease. In Vitória, state of Espirito Santo, Brazil, PLA in children is frequently associated with helminthic infections and eosinophilia. We hypothesize that nematode infection with larvae migrating through the liver is a predisposing factor for PLA, because the infection induces immunomodulation and likely trapping of bacteria in liver granulomas. In this report, we describe observations of 22 cases of PLA in children studied at autopsy (16 cases) or in surgical biopsies (6 cases), including 17 boys and 5 girls ranging in age from 1 to 13 years (mean 4.6 years, median 3.5 years). Multiple abscesses in both lobes were found in 13 cases and a single abscess was found in the right lobe in 10 cases. All cases showed histologically classical pyogenic inflammation without morphological evidence of amoebiasis. In six cases there were granulomas similar to those caused by larva migrans visceralis (from Toxocara or other nematodes) in liver tissue not affected by the abscess. Nematode antigens in central areas of necrosis of granuloma in all six cases and fragments of a larva, possibly of Toxocara, were found on samples immunohistochemically stained with polyclonal anti-Toxocara antibodies. There were numerous eosinophils in abscesses with Charcot-Leyden crystals. Eosinophils were found frequently in portal triads far from the abscess wall. In four cases, in which bile duct ascariasis was found, worms were noted in the bile ducts, and eggs were found in liver parenchyma surrounding the abscess in two cases. Foreign-body granulomas were found in one case in which penetrating trauma was the cause of abscess. In one case there was one histiocytic granuloma whose origin was not determined. The observation of six cases of granuloma similar to larva migrans visceralis (or produced by other nematode larva) in liver tissue not directly affected by the abscess supports the hypothesis that helminth infections with larva migrating through the liver are a predisposing factor for pyogenic hepatic abscess in children.