Mixed Bag for Monday, June 1st, 2026

Contributed by Centro Hospitalario Pereira Rossell
Dra. Azucena Riviezzi, and Dra. Leticia Gadea.

History

3 year old male, with history of recurrent wheezing, global developmental delay, immunizations up to date.

HPI: The patient presented with fever of 48 hours’ duration associated with chills and vomiting.

PE: Cutaneous and mucosal pallor; otherwise unremarkable.

Laboratory findings: Hb 7.3 (low MCV and MCH / increased RDW), WBC 35,000 (predominantly eosinophilic with severe eosinophilia), PLT 74,000, CRP 55.

Abdominal and urinary tract ultrasound and a chest X-ray were ordered.

Images (Click any image to enlarge)

Liver with regular contours and normal shape and size. Numerous oval hypoechoic lesions with ill-defined margins are observed, without vascularization on color Doppler and without mass effect. They involve both lobes. The largest lesion is located in the periphery of segment 7 and measures 10 mm.
Liver with regular contours and normal shape and size. Numerous oval hypoechoic lesions with ill-defined margins are observed, without vascularization on color Doppler and without mass effect. They involve both lobes. The largest lesion is located in the periphery of segment 7 and measures 10 mm.
Liver with regular contours and normal shape and size. Numerous oval hypoechoic lesions with ill-defined margins are observed, without vascularization on color Doppler and without mass effect. They involve both lobes. The largest lesion is located in the periphery of segment 7 and measures 10 mm.
The spleen is enlarged, with normal echogenicity and no focal lesions. No images suggestive of microabscesses are identified.
Multiple enlarged mesenteric lymph nodes of inflammatory appearence are identified.
A solid intraventricular lesion is identified in the right ventricle, with ill-defined margins and heterogeneous density and enhancement. Its boundaries and relationship with the ventricular walls cannot be clearly defined, as a gated study was not available.
Multiple solid pulmonary micronodules and nodules are identified, well-defined with irregular margins and surrounded by a ground-glass halo, with a random distribution.
Nodule surrounded by ground-glass halo
CT of the abdomen and pelvis was performed including non-contrast, late arterial, and portal venous phases. The liver is enlarged for the patient’s age, with hepatomegaly measuring 132 mm in the right midclavicular line (expected value for age: 86 mm). There are multiple solid nodular lesions, diffusely distributed throughout both hepatic lobes, showing enhancement in the late arterial phase and appearing hypodense on the portal venous phase. The lesions are rounded and poorly defined.

Question

Based on the imaging findings, which etiology is most likely?

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Correct answer

Visceral Larva Migrans

Discussion

In the setting of a previously healthy child with relevant environmental exposure, acute–subacute presentation, marked anemia and eosinophilia, and compatible imaging findings, toxocariasis represents the leading diagnostic consideration.

Imaging findings described in the literature for this pathology include nonspecific hepatic and pulmonary manifestations. Hepatic lesions may result from eosinophilic infiltration, granuloma formation, or abscesses. On computed tomography (CT), they typically appear as small, ill-defined, hypoattenuating lesions during the portal venous phase, with an oval or elongated morphology in most cases. Enhancement during the arterial phase, either peripheral or diffuse, is uncommon, and in many patients the lesions are only appreciable during the portal venous phase. In the present case, we observed an unusual pattern of presentation according to the literature, as the lesions initially behaved as hypervascular lesions during the arterial phase and subsequently appeared as hypoattenuating lesions during the portal venous phase, which represents the most frequently described pattern of presentation.

On ultrasound, hepatic lesions are usually multiple, small, hypoechoic, and poorly defined, with an oval or elongated appearance, similar to the findings observed in the present case. Doppler evaluation may demonstrate peripheral vascular flow without central vascularization, although this finding is uncommon.

Pulmonary involvement on CT typically manifests as multiple subcentimeter nodules, most of which demonstrate a surrounding ground-glass halo, as seen in the present case. These lesions are likely related to eosinophilic infiltration of the alveolar septa. These nodules may show migratory behavior during follow-up imaging. Additional findings can include areas of ground-glass opacity.

Subsequently, serologic testing returned positive for toxocariasis, along with a favorable clinical response to treatment with antibiotics and albendazole.

The pathogenesis of endomyocardial fibrosis (as seen on the additional images) remains poorly understood and is considered multifactorial. Parasitic infestation, poverty, malnutrition, and genetic predisposition may trigger inflammation and immunomodulation, inducing a profibrotic state that ultimately leads to endomyocardial fibrosis and ventricular apical obliteration. The patient presented in this case exhibited several of the aforementioned factors.

Differential diagnosis

The differential diagnosis in this case includes both infectious/parasitic and neoplasic etiologies. The combination of hepatomegaly, multiple hepatic nodular lesions, pulmonary nodules, and marked eosinophilia raises concern for a systemic process with multiorgan involvement.
The differential diagnosis may include: other parasitic infections, miocardic sarcoma, hematologic malignancies such as lymphoma or metastases from an unknown primary.

Additional images

Subsequently, a cardiac MRI was performed for further characterization of the intracardiac mass, demonstrating tissue characterization features consistent with endomyocardial fibrosis (blue), with isolated right ventricular involvement and an associated intracavitary thrombus (red). The pathogenesis is not fully understood and is likely multifactorial: parasitic infestation, poverty, malnutrition, and genetic predisposition may trigger inflammatory and immunomodulatory mechanisms, leading to a profibrotic state that results in endomyocardial fibrosis and progressive ventricular apical obliteration.

References

  • Kraft, J., et al. (2023). Body imaging of bacterial and parasitic zoonoses: Keys to diagnosis. Radiographics, 43(4), e220134. https://doi.org/10.1148/rg.220134
  • Solomon, J., et al. (2025). Multimodality imaging of helminthic infections. Radiographics, 45(1), e240095. https://doi.org/10.1148/rg.240095
  • Helminthic diseases in the abdomen: An epidemiologic and radiologic overview. (n.d.). Radiographics.
  • Microorganisms Research. (2023). Toxocariasis: Clinical and radiologic features. Microbiology Research, 16, 58.
  • Chang, S., Lim, J. H., Choi, D., Park, C. K., Kwon, N.-H., Cho, S.-Y., & Choi, D.-C. (2006). Hepatic visceral larva migrans of Toxocara canis: CT and sonographic findings. American Journal of Roentgenology, 186(1), 158–161. https://doi.org/10.2214/AJR.04.1719