IJCRI – International Journal of Case Reports and Images, Vol. 3 No. 6, June 201 2. ISSN – [0976-31 98]

IJCRI 201 2;3(6):7–1 2.www.ijcasereportsandimages.com

Case series of visceral larva migrans in the liver:CT and MRI findingsShalini Thapar Laroia, Archana Rastogi, Shiv Sarin

ABSTRACTIntroduction: Visceral larva migrans (VLM) isan uncommon parasitic infection mostcommonly caused by Toxocara canis andToxocara cati. Imaging features of hepatic VLMon contrast enhanced computed tomography(CECT) include presence of small, single ormultiple (usually less than two cms in diameter)hypovascular eosinophilic abscesses seenenhancing only on portal venous phase (PVP) ontriple phase liver study. Review of literaturerevealed that CT and peripheral eosinophilia inthe blood has been the mainstay of clinicaldiagnosis in majority of case reports and largerstudies. Case Series: We have used 3 Tesla (3T)magnetic resonance imaging (MRI) in additionto CT for diagnosis of hepatic visceral larvamigrans in three patients with special emphasison T1 weighted and diffusion weightedsequences. MRI and CT images showedinteresting findings such as hyperintense rim ofthe lesions on T1 weighted sequence andhyperintensity on diffusion weighted images(DWI) at b values of 1000 with associated

restriction on the corresponding ADC maps.Conclusion: We would like to emphasize theimportance of echo planar imaging and T1weighted sequences of the liver in addition toroutine dynamic CT and conventional MRIsequences for assessment of suspectedeosinophilic abscesses in visceral larva migranspresenting as focal liver lesionsKeywords: Visceral Larva migrans, MRI, DWI,ADC, T1 weighted sequence, Eosinophilicabscesses

*********Laroia ST, Rastogi A, Sarin S. Case series of viscerallarva migrans in the liver: CT and MRI findings.International Journal of Case Reports and Images2012;3(6):7–12.

*********doi:10.5348/ijcri­2012­06­129­CS­2

INTRODUCTIONThe second­stage larvae of nematodes (Toxocara isthe commonest) are sometimes accidentally ingested byhuman beings and are released in the small bowel, fromwhere they enter the portal venous system through theintestinal walls and infest the liver, lung, eyes etc. [1–3]imaging features of hepatic lesions in visceral lervamigrans (VLM) are indicative but not characteristic ofthe disease and need correlation with laboratoryparameters like antigen serology, cytology andeosinophilic counts. However, with the help of triplephase CT, advanced MRI and newer sequences likeDWI, imaging diagnosis can be made more specific. Wepresent three cases with different clinical presentationswho underwent triple phase CT in one case and MRIwith diffusion weighted imaging (DWI) in two cases.

CASE SERIES OPEN ACCESS

Shalini Thapar Laroia1 , Archana Rastogi2, Shiv Sarin3

Affi l iations: 1Assistant Professor, Radiology department,Institute of Liver & Bil iary sciences, New Delhi, India;2Associate Professor, Department of Hepato Pathology,Institute of Liver & Bil iary sciences, New Delhi, India;3Director ILBS and Professor of Hepatology and TransplantHepatology, Institute of Liver & Bil iary sciences, New Delhi,India.Corresponding Author: Dr. Shalini Thapar Laroia, L-1Krishan Vatika, DLF Westend Farms, Govind Sadan Marg,Chattarpur, New Delhi-1 1 0030, India; Ph: 091 -981 0757973,091 -9811 01 5080; Fax: 091 -011 -26806356; Email-thaparshalini@gmail .com

Received: 02 March 201 2Accepted: 07 Apri l 201 2Published: 30 June 201 2

Laroia et al. 7

IJCRI – International Journal of Case Reports and Images, Vol. 3 No. 6, June 201 2. ISSN – [0976-31 98]

IJCRI 201 2;3(6):7–1 2.www.ijcasereportsandimages.com Laroia et al. 8

They were diagnosed as eosinophilic (VLM) abscesseson imaging and proven with cytology and lab criteria[12]. The informed consent for the report was receivedfrom the patients and the ethics committee of ourhospital.

CASE SERIESCase 1: A 35­year­old female patient presented withintermittent high grade fever with chills for a durationof 1.5 years. She had been partially treated during pastepisodes of fever with antibiotics tazabactum andmetronidazole. No definite history of contact withanimals or pets was obtained. At the time ofpresentation, her total leukocyte counts were7,400/mm3, eosinophil count was 4% and ESR wasraised to 75 mm/1st hr. Hydatid serology was negative.Triple phase CT of the liver showed few coalescing,hypo­attenuating, solid, rounded lesions with minimalvascularity (Figure 1A­C) seen only on portal venousphase. Ultrasound guided FNAC of the liver lesion(Figure 1D) showed charcot leyden crystals with mixed

inflammatory and proteinaceous material, predominanteosinophils and poorly formed epitheloid granulomascharacteristic of eosinophilic abscesses of parasiticorigin. Treatment with albendazole led to remarkableregression in size of these lesions at follow up.Case 2: Fifty­eight years male with low grade feveroff and on for past three months was investigated andfound to have raised total leukocyte count of11,500/mm3, high ESR ­ 70 mm/1st hr, increasedeosinophil count (38%) with altered liver enzymes andmildly raised total bilirubin of 2.5 mg/dl. His hydatidserology was negative. MRI was done for evaluation andmultiple well defined thick walled T2 hyperintenselesions (Figure 2A) with brightness on diffusionweighted images (b value 1000) (Figure 2B, C) andcorresponding restriction on ADC was seen (Figure 2D,E). In addition these lesions had T1 hyperintensity alongtheir peripheries Figure 2F), possibly due to highcellularity. Parasitic eosinophilic abscesses due to VLMwere diagnosed in correlation with peripheraleosinophilia.Anti­helminthic treatment showed significantdecrease in lesion size and clinical symptoms.

Figure 1: A) Arterial phase of CECT of the liver shows ill defined, 1–2 cms ovoid lesions in the right lobe with mild peripheralenhancement, B) Portal venous phase shows well defined rim enhancement of the conglomerated lesions in segment six of rightlobe of liver, C) Delayed phase image shows faint enhancement of the lesions, D) USG­guided FNA air­dried smear shows clustersof eosinophils (thick arrows), Charcot­Leyden crystals (thin arrows) and group of benign reactive hepatocytes (medium thicknessarrow) (Giemsa, x100).

IJCRI – International Journal of Case Reports and Images, Vol. 3 No. 6, June 201 2. ISSN – [0976-31 98]

IJCRI 201 2;3(6):7–1 2.www.ijcasereportsandimages.com Laroia et al. 9

Figure 2: A) T1 weighted axial sequence of the liver MRI at 3T shows hypointense conglomerating ovoid lesions with peripheralhyperintense rim, B) T2 weighted SSFSE sequence shows hyperintense lesions of varying sizes 1–2.5 cms appearing as a cluster, C,D) DWI at b value of 1000 shows hyperintensity of the above lesions, which are well appreciated on these images, E, F) ADC mapsof the above lesions show areas of restriction appearing hypointense within the lesions in the right lobe.

IJCRI – International Journal of Case Reports and Images, Vol. 3 No. 6, June 201 2. ISSN – [0976-31 98]

IJCRI 201 2;3(6):7–1 2.www.ijcasereportsandimages.com Laroia et al. 1 0

Case 3: Fifty one years male patient who waspreviously treated for non resolving atypical liverabscess was referred for an MRCP and upper abdominalscan to rule out biliary cystadenomas. His amebic andhydatid serologies were negative with marginally alteredliver enzymes and raised bilirubin of 3.4 mg/dl. Thetotal leukocyte counts were normal with mild eosinophiliaof 8%.MRI scan showed conglomerating T2 hyperintenselesions with thick nodular regions along the walls(Figure 3A, B). T1 hyperintense rim of few of theselesions was noted (Figure 3C). On diffusion weightedsequence the abscesses showed hyperintensity at b value1000 with corresponding restriction on ADC maps(Figure 3D­G). A diagnosis of parasitic eosinophilicabscesses was suggested and proven on ultrasoundguided biopsy, which showed eosinophils and charcotleyden crystals with necrosis.

DISCUSSIONVisceral larva migrans is a systemic manifestation oftoxocariasis. It is usually an asymptomatic or vaguelysymptomatic condition which is caused by migratinglarvae of Toxocara in the liver, lungs eyes etc. VLM has aworldwide prevalence, although there is a strongpredilection for the tropical countries and southeastAsia [1]. The wide range of symptoms which aredependent on the organ involved, the intensity of larvaload, infection and host immune response determinethe course of the disease. Young adults and childrenwho are in close contact with pets and animals or haveincreased exposure to public places and parks withcontaminated soil are at a higher risk of contracting thedisease [4, 5]. An unusual method of contracting thisdisease is through ingestion of raw infected meatcontaining the infective encapsulated larvae form of T.canis, reported by Ishibashi et al. [4]. None of thepatients in the series presented above had history ofanimal contact or eating raw meat and hence clinicalsuspicion of the disease entity of parasitic origin couldnot be made.As the name VLM suggests, larval migration inorgans such as liver and lung occurs, which causesreactive eosinophilic infiltration, parenchymaldestruction, granuloma or eosinophilic abscessformation [5]. Eosinophilic abscess on histopathologyshows enlarged eosinophils, necrosis, debris anddestroyed liver architecture with infiltrates andinflammatory cells such as neutrophils and lymphocytes[5]. The larva may also be visualized rarely within tissuespecimens.Imaging by ultrasound, CT and MRI is an attributeto these pathological findings.There have been series and case reports of VLM[2–8], and the radiologic findings have been describedpredominantly on ultrasound, CT and conventionalsequences on MRI. Chang et al. described the CT andultrasound findings of a retrospective analysis of 70serologically proven hepatic VLM [1]. On contrast CT of

the liver, lesions have been described as hypodense,non­subcapsular in location, usually multiple innumber, ill­defined, oval angular or trapezoid lesionsmeasuring 1.0–1.5 cm in diameter [4, 6, 10]. Differentshapes and margins of these lesions depend on the typeof destruction of the liver parenchyma by the abscesses[10]. They have well defined margins and walls withnodularity which can sometimes be seen on noncontrast and dynamic triple phase MRI, studies. Theportal venous phase best depicts this lesion nodularityand margin. Faint vascularity seen on arterial andequilibrium phases have been described by Azuma et al.and Kim et al. [9, 10]. Characteristic T1 weightedhypointensity­isointensity and T2 weightedhyperintensity is documented by Kim et al. [9].The differentiation from metastatic lesions is doneby looking for fuzzy margins, elliptical shape anduniform sized lesions of 1–2 cm diameter. Theconspicuity of the eosinophilic abscesses is most on theportal venous phase, which may later change size andpositions, characteristic of migration of larva in the liveras opposed to metastases, supporting the diagnosis ofVLM [1, 10, 11].Some lesions have been seen to enhance on hepaticarterial phase but do not show any washout onequilibrium and delayed phases and hence can bedifferentiated from the nodules of hepato cellularcarcinoma (HCC) [10].Differentiation from focal eosinophilic infiltrates iswith the help of MRI and recently with the help ofdiffusion weighted imaging, which does not show anyrestriction of these benign lesions in the liver [11].In the case studies presented above we analyzed theCT and MRI findings of eosinophilic abscesses of viscerallarva migrans in patients with incidentally detected liverlesions, with hypereosinophilia, raised ESR and leucocytecount in two of them. We demonstrate the characteristicCT findings of VLM with a few additional interestingfeatures on MRI that are helpful in differentiating themfrom other benign lesions, tumours and metastases inthe liver. On contrast CT the lesions appeared coalescing,predominantly in the periportal and non­subcapsularregion with well defined margins, hypoattenuation(approximately 35 HU) and well visualized on the portalvenous phase.On non­contrast MR study, two kinds of imagingfindings were shown: the first was the well definedhyperintense rim of the abscesses and the second wasthe restriction of these lesions on ADC mapscorresponding to the diffusion images. Diffusionweighted sequences obtained at b values of 0 and 1000on the 3Tesla MRI system demonstrated hyperintensityof the parasitic abscesses. Ahn et al. described the use ofgadoxetic acid­enhanced MRI to diagnose focaleosinophilic infiltrates [11] in cases where lack ofinformation from DWI sequencing of the focalinfiltrates was shown. Their study group consisted ofeight patients. ‘Eosinophilic infiltrates’ which theydescribed has been proven to be a different entity fromVML induced eosinophilic abscesses as described byKim et al. [10].

IJCRI – International Journal of Case Reports and Images, Vol. 3 No. 6, June 201 2. ISSN – [0976-31 98]

IJCRI 201 2;3(6):7–1 2.www.ijcasereportsandimages.com

Figure 3: A) Coronal SSFSE T2 weighted sequence shows 3–4 cms lobulated rounded lesions with thick hypointense walls andhyperintensity within. Smaller one cm lesion is brighter than other lesions and is likely to represent a cyst, B) Axial T2 weightedSSFSE sequence showing similar lesions as in figure A, C) Axial T1 lava sequence showing well defined hyperintensity of the wallsof the lesions. which are hypointense to rest of the liver; D, E) DWI at b value of 1000 showing bright lesions with hypointensenodular walls and corresponding restriction on the ADC maps; F, G) DWI at b value =1000 shows a smaller brighter lesion to theright of a mildly hyperintense larger lesion without restriction on corresponding ADC map (appearing bright on both images F andG) suggestive of a simple cyst.

Laroia et al. 11

IJCRI – International Journal of Case Reports and Images, Vol. 3 No. 6, June 201 2. ISSN – [0976-31 98]

IJCRI 201 2;3(6):7–1 2.www.ijcasereportsandimages.com

The presence of T1 hyperintense rim around theperiphery of these lesions could possibly be due toincreased cellularity in this region.To our knowledge there is no study in literaturedemonstrating the importance of these specific MRimaging characteristics in visceral larva of the liver.

CONCLUSIONIn conclusion, we would like to emphasize theimportance of echo planar imaging of the liver inaddition to routine dynamic CT and conventional MRIsequences for assessment of suspected eosinophilicabscesses in visceral larva migrans presenting as focalliver lesions.

*********Author ContributionsShalini Thapar Laroia – Substantial contributions toconception and design, Analysis and interpretation ofdata, Drafting the article, revising it critically forimportant intellectual content, Final approval of theversion to be publishedArchana Rastogi – Substantial contributions toconception and design, Drafting the article, Finalapproval of the version to be publishedShiv Sarin – Substantial contributions to conceptionand design, Drafting the article, revising it critically forimportant intellectual content, Final approval of theversion to be publishedGuarantorThe corresponding author is the guarantor ofsubmission.Conflict of InterestAuthors declare no conflict of interest.Copyright© Shalini Thapar Laroia et al. 2012; This article isdistributed under the terms of Creative Commonsattribution 3.0 License which permits unrestricted use,distribution and reproduction in any means providedthe original authors and original publisher are properlycredited. (Please see www.ijcasereportsandimages.com/copyright­policy.php for more information.)

REFERENCES1. Chang S, Lim JH, Choi D, et al. Hepatic viscerallarva migrans of Toxocara canis: CT andsonographic findings. AJR Am J Roentgenol 2006Dec;187(6):W622–9.2. Glickman LT, Magnaval JF, Domanski LM, et al.Visceral larva migrans in French adults: a newdisease syndrome? Am J Epidemiol1987;125:1019–34.3. Hayashi K, Tahara H, Yamashita K, et al. Hepaticimaging studies on patients with visceral larva

migrans due to probable Ascaris suum infection.Abdom Imaging 1999;24:465–9.4. Ishibashi H, Shimamura R, Hirata Y, Kudo J,Onizuka H. Hepatic granuloma in toxocaralinfection: role of ultrasonography inhypereosinophilia. J Clin Ultrasound1992;20:204–10.5. Kaplan KJ, Goodman ZD, Ishak KG. Eosinophilicgranuloma of the liver: a characteristic lesion withrelationship to visceral larva migrans. Am J SurgPathol 2001;25:1316–21.6. Bhatia V, Sarin SK. Hepatic visceral larva migrans:evolution of the lesion, diagnosis, and role of high­dose albendazole therapy. Am J Gastroenterol1994;89:624–7.7. Fan CK, Lan HS, Hung CC, et al. Seroepidemiology ofToxocara canis infection among mountain aboriginaladults in Taiwan. Am J Trop Med Hyg2004;71:216–1.8. Baldisserotto M, Conchin CF, Soares MG, AraujoMA, Kramer B. Ultrasound findings in children withtoxocariasis: report on 18 cases. Pediatr Radiol1999;29:316–9.9. Azuma K, Yashiro N, Kinoshita T, Yoshigi J, Ihara N.Hepatic involvement of visceral larva migrans due toToxocara canis: a case report­­CT and MR findings.Radiat Med 2002 Mar­Apr;20(2):89­2.10. Kim YK, Kim CS, Moon WS, Cho BH, Lee SY, LeeJM. MRI findings of focal eosinophilic liver diseases.AJR Am J Roentgenol 2005;184:1541–8.11. Ahn SJ, Choi JY, Kim KA, et al. Focal eosinophilicinfiltration of the liver: gadoxetic acid­enhancedmagnetic resonance imaging and diffusion­weightedimaging. J Comput Assist Tomogr 2011 Jan­Feb;35(1):81­5.12. Glickman L, Schantz P, Dombroske R, Cypess R.Evaluation of serodiagnostic tests for visceral larvamigrans. Am J Trop Med Hyg 1978;27:492–8.

Laroia et al. 1 2