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Year : 2003  |  Volume : 13  |  Issue : 3  |  Page : 301-302
Isolated cerebral alveolar echinococcus : New finding on contrast MR

G.B. Pant. Superspeciality Hospital and Maulana, Azad Medical College New Delhi-2, India

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A 50-year-old male was admitted with tonic clonic seizure. There was no evidence for systemic parasitic disease. CSF analysis showed mild eosinophillic pleocytosis. MRI suggested the evidence of hydatid cyst. with characteristic findings of enhancing membrane on post contrast images.

Keywords: Brain, Echinococcus, Contrast MR

How to cite this article:
Sharma A, Saurabh, Sharma N, Puri S. Isolated cerebral alveolar echinococcus : New finding on contrast MR. Indian J Radiol Imaging 2003;13:301-2

How to cite this URL:
Sharma A, Saurabh, Sharma N, Puri S. Isolated cerebral alveolar echinococcus : New finding on contrast MR. Indian J Radiol Imaging [serial online] 2003 [cited 2021 Jan 28];13:301-2. Available from:
The adult echinococcus worm lives attached to the intestinal villi of primary hosts, red and white foxes, field mices and voles. The larval stage occurs in a variety of animals, Including humans, accidently infected with direct contact with rodents or ingestion of contaminated vegetables or water. After being ingested, embryos hatch in the Duodenum and the embryos penetrate the intestinal wall and the portal circulation.

The main metastatic pathway of AE extends from liver to the inferior vena cava and Right atrium, Embryos may get implanted in lung parenchyma forming a source of metastases to the systemic arterial circulation [1].Cerebral AE lesions are usually Supratentorial mainly in territory of MCA.In our case there was no primary focus in the Liver to suggest the hematogenous spread.

   Case Report Top

A 55 year-old man was admitted with headache and generalized tonic clonic seizure.

Past medical history was unremarkable.CSF findings showed a mild pleocytosis. Axial Sagittal and coronal plane MRI was performed taking both T1 and T 2 sequences. On T1, there was well circumscribed hypointence mass lesion in left parietal lobe [Figure - 1].On T2, it became hyper intense [Figure - 2].There was an evidence of surrounding edema of moderate degree. Axial and coronal contrast enhanced T1 images showed a well defined hypo intense lesion with peripheral rim enhancement [Figure - 3]. In addition to this, there was an enhancing membrane in the mass lesion.MR diagnosis of hydatid cyst was suggested. Other imaging investigations and serological tests revealed no definite hints for a systemic disease.

   Discussion Top

Intracranial hydatid cysts, although still rare, are being seen with increasing frequency.

Clinical presentation is due to mass effect by the cyst. Patients present with nausea, headache, vomiting, papilloedema, hemiparesis and cranial nerve palsies [1],[2]. MRI AND CT appearances of cerebral AE lesions have been reported [2],[3],[4].They are generally unilocular cystic masses with sharp margins. Calcification and surrounding edema are common. Contrast enhancement occurs around the cysts in the inflammatory zone. A few cases have shown enhancement pattern including heterogenous, ring, peripheral and nodular enhancement [2],[3],[4].Another report described AE lesions without enhancement, a lack of enhancement may be a useful clue in differentiating these lesions from cerebral abscesses and tuberculomas [3],[5].In our case, the isolated lesion showed peripheral /rim enhancement and enhancement of the membrane in the centre.Otherwise,the lesion was hypo intense on T1 and hyper intense on T2 weighted images. Coronal flair images showed the lesion as hyper intense The pattern described in our case may be able to distinguish these lesions from tumours tuberculomas and brain abscesses.

   References Top

1.Reittner P,Szolar DH,Shmid.Systemic manifestation of echinococcus alveolaris infection Comput Assist Tomor 20:1030-1032.   Back to cited text no. 1    
2.El-Sham O,Amer T,El Atta.Magnetic resonance imaging of simple and infected hydatid cysts of brain.Magn Nucl Med.2001;19(7):965-974.   Back to cited text no. 2    
3.Tunaci M,Tunaci A,Engin g,Ozkorkmaz B,Ahishali B,Rosanes I.MRI of cerebral Echinococcosis. Neuroradiology 1999;41(11):844-846.   Back to cited text no. 3    
4.Tunzun M,Hekimoglu B.Hydatid disease of the CNS:Imaging features.AJR 1998;171(6):1497-1500.   Back to cited text no. 4    
5.Ben said AH,Dietemann JL,deLa Palavesa.Intracranial alveolar echinococcosis: CTand MRI.Neuroradiology 1994;36(4):289-291.  Back to cited text no. 5    

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[Figure - 1], [Figure - 2], [Figure - 3]


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