Visceral larva migrans (VLM) is a systemic presentation of migrated nematodal larvae through human viscera. The liver is most commonly affected because of portal venous blood supply.¹ It is usually underdiagnosed and rarely kept in the differential diagnosis of hepatic space-occupying lesions (SOLs). This entity should also be considered in the differentials of patients with sustained eosinophilia showing typical imaging findings. Imaging findings are subtle and must be differentiated from other close entities. Diagnosis requires a strong clinical suspicion, serology, radiology such as magnetic resonance imaging (MRI)/computed tomography (CT) abdomen, and clinical-radiological correlation. There are only a few case reports and short case series available in the literature on VLM.^1-7 In clinical practice, the majority of cases are still managed as amoebic or pyogenic hepatic abscesses. Here, we are reporting six cases of VLM, who presented to us with non-resolving pain in the abdomen, fever, and persistent liver SOL with eosinophilia.

This study was carried out in the Gastroenterology department in a tertiary care center between July 2022 and June 2023. The records of six patients of VLM were reviewed. These patients presented to us with complaints of fever, pain in the abdomen, malaise, and other constitutional symptoms. They had atypical SOL in the liver on ultrasonography (USG) and/or CT abdomen and were being treated as liver abscesses with antibiotics and nitroimidazole drugs in the past with non-resolution of symptoms. Study patient’s detailed history, clinical examination findings and laboratory tests comprising a hemogram, erythrocyte sedimentation rate, kidney function test, liver function test, electrolytes, and a plain abdomen radiograph were reviewed. Other specific blood investigations, including alpha-fetoprotein (AFP), immunoglobulin levels, and serologies (amoebic, hydatid, and Toxocara canis) were also noted. Triple-phase CT abdomen was done to characterize the lesions, and if needed, a triple-phase MRI abdomen with diffusion-weighted imaging (DWI) was done for further details to achieve a definite diagnosis. The USG-guided fine needle aspiration cytology (FNAC) of liver SOL was done for histopathological examination. After diagnosis, all six patients were given albendazole 400 mg twice daily for four weeks, along with antihistaminic drugs and other supportive treatment, which were continued for three months. These patients were followed up for three months clinically to confirm the resolution of symptoms and lesions. Informed consent in writing was taken from the subjects and their relatives to use the data and publish it for scientific purposes in an anonymized manner.

Demographics and clinical presentation: Six patients median age 27.5 years (range15-41) were included in the study with male to female ratio of 1:1. Presenting symptoms in most of the patients were fever, pain in the right hypochondrium and associated malaise in one patient for 2-6 weeks. Most of the patients had received fluoroquinolones and nitroimidazole antibiotics for four weeks without improvement in symptoms. On examination, these patients had pallor and hepatomegaly without palpable spleen or lymph node. The baseline demographic and clinical presentation of all the six patients are given in Table 1. Two patients had history of pets (dogs) in house while three patients were non-vegetarian by diet.

Laboratory Features: The median hemoglobin of the study patients was 10.7 g/dl (range 8.9-12.2), absolute eosinophil count was 2020 cell/mcL (range 860-4398) and serum immunoglobin E level was 150 IU/ml (range 124-162). Hydatid and amoebic serology were negative in all the patients, while Toxocara serology by enzyme-linked immunosorbent assay (ELISA) came out to be positive in all. Peripheral smear showed eosinophilia in all the patients. All the patients also underwent USG-guided FNAC of hepatic lesions, which showed degenerated, mixed inflammatory cells primarily consisting of eosinophils along with necrosis and a considerable number of Charcot Leyden crystals, with no parasites observed in the smears as shown in (Figure 1d). The detail of laboratory features of all the six patients are given in Table 1.

Imaging Features: Abdominal ultrasound showed a multi-cystic hypoechoic lesion in both hepatic lobes with internal echoes and vascularity in all the patients. Triple-phase abdominal CT showed several round, thick-walled lesions and internal septations (Figure 1a). For further characterization of lesions, a triple-phase MRI of the abdomen was done, which showed multiple conglomerated multiloculated cystic lesions showing T1 hypointense and T2 hyperintense signal intensity with internal septations and honey combing with restricted diffusion on diffusion-weighted (DW) images (Figure 1b, 1c, 2 and 3). The lesions showed progressive enhancement of the peripheral wall and internal septations, favoring atypical hepatic abscess or VLM. Because of imaging findings and peripheral eosinophilia, a provisional diagnosis of hepatic VLM was considered. The detail of imaging features are given in Table 1 and the given size of lesions is the size of largest lesion in the individual patients.

Treatment and follow-up: Based on available investigations, hepatic VLM was diagnosed. The subjects were given oral albendazole 400mg twice a day for four weeks. On a follow-up visit at the end of 3 months, all the patients had a decrease in the percentage of eosinophil counts and a reduction in the size of hepatic lesions on USG along with an improvement in clinical symptoms as shown in Table 1.

The VLM is a syndrome distinguished by chronic eosinophilia, eosinophil-rich hepatic granulomatous lesions, and some degree of lung involvement. It should be considered as one of the differential diagnoses of liver abscesses, as shown in a recently published small case series.⁸ The etiological agent is larvae of genus Toxocara, subspecies Toxocara canis or catis.² It occurs due to the migration of second-stage larvae through the human viscera. Cats and dogs are the most typical primary hosts for the disease-causing nematodes for Toxocara catis and Toxocara canis, respectively.¹ The estimated seroprevalence of human toxocariasis is 19% worldwide and 19.6% in India.⁹ 

In conclusion, hepatic VLM should also be a differential in patients with sustained eosinophilia, showing the typical imaging findings. The imaging findings are usually subtle and must be differentiated from other close entities. Diagnosis requires a strong clinical suspicion, serology, radiology such as MRI/CT abdomen, and clinical-radiological correlation along with cytology.