Large Hydatid Liver Cyst

                                           Large Hydatid Liver Cyst


                                                   CASE STUDY

Steve Ramsey, PhD                                                   

MSc Medical ultrasound

BSc Diagnostic Imaging



The authors declare no conflict of interest and no commercial affiliations.

We thanks Dr. Karen Hoffman, and Siti Hamid for their great assistance 

May, 2019


Hydatid live disease is still endemic in certain part of the world.

The diagnosis of Uncomplicated Hydatid cyst of the liver depends on clinical suspicion.

Ultrasonography is one of the imaging modality that can detect these cysts along with CT scan and MRI. The diagnosis can then help the doctor to better manage and treat these cysts. Hydatid disease is a parasitic infestation by a tapeworm Echinococcus.

It affects both humans & other mammals such as sheep, goats & horses etc 1

Introduction: In humans there are 3 different forms 1-3

1: Cystic (unilocular echinococcis)—most common form—caused by E. granulossus

2: Alveolar echinoccosis—caused be E multilocularis.

3: Polycystic echinoccosis—caused by E Vogeli.

Areas of world where high incidence rate is—Northern hemisphere including North Europe, Mexico, Some Latin American countries & SOME ASIAN COUNTIRES 2-5     

Life Cycle

Eggs > larvae > adult worm

Eggs pass through feces of definitive host & ingestion of these eggs leads to infection in intermediate host

From Embryo releases from an egg develops a hydatid cyst which grows 5-10cm in the first year & is able to survive within an organ for years. 5-7


In humans 75% of cases localize to liver & develops as a slowly growing mass (cyst) in body usually filled with clear fluid (Hydatid fluid) – (Protein, Albumin, Codounis, Poly dorides, Antigen-antibodies, & Alpha/Beta/Gama globulins)

Patients could be asymptomatic and if symptomatic then usually presents with abdominal pain, abdominal tenderness, hepatomegaly, fever, jaundice.

If a cyst gets rupture in body due to trauma or during surgical removal it can lead to anaphylactic reaction (fever, pruritis, edema of lips & eyelids, dyspnoea, stridor).3-7


CT—98% accuracy




Casoni test, 70% sensitive but now abandoned because of low sensitivity & availability of better tests

X-ray abdomen

Blood CP




75 years old Vietnamese lady with out pain or fever arrived to the ultrasound department for abdominal ultrasound.The physician wanted to rule out hepatomegaly as he felt that part of her liver was enlarged.Complete abdominal ultrasound was done and revealed a complex mass covering most of segment 4A/ 4B and part of the left lobe. (Fig 1-5)The mass was complex, predominantly cystic and measuring= 51X 43 X 40 mm, with a single septation, and daughter cyst measuring 10 by 11 mm. Other small calcifications were also noted in the right lobe of liver. The mass contain mobile fatty debris that caused false color flow (artifacts), and had no vascularity. After the CT scan result the Radiologist reached the conclusion that this mass was Hydatid cyst, given that the patient lived most of her life in the farm in one of Vietnam village and by the cystic mass characteristics. The ultrasound images showed few specks of calcification and septation .  


Surgical removal of cyst with chemotherapy with Albendazole +/- Metronidazole before and after surgery

If cyst is impractical to remove PAIR (puncture-aspiration-injection-reaspiration) is another option

Now studies looking at new treatments involving percutaneous thermal ablation (PTA) or laparoscopic cyst removal


Figure 1: Large complex liver cyst 51 by 43 by 41 mm, with septation, daughter cyst, and mobile debris

Figure 2: False color flow (artifacts) caused by movements of the floating debris    (Protein, Albumin, Codounis, Poly dorides, Antigen-antibodies, & Alpha/Beta/Gama globulins)

Figure 3: Liver 4A/ 4B segment it shows the capsulated edge of the complex cyst with septation and calcification.

Figure 4: Daughter cyst measuring 10 x11 mm close to the larger Hydatid liver cyst.

Figure 5: Right lobe of liver calcification (possible calcified larva)


In human Hydatid disease is caused by the larvae of a flat tapeworm, E granulossus.

It is seen worldwide and is endemic in some areas of the world. This case was found in Calgary, Alberta, Canada in a Vietnamese female patient that used to be a rice farmer in Vietnam.  Human are intermediate host and an end point in the parasite’s life cycle.

The life cycle alternates between herbivores and carnivores, for example, sheep and dogs.

When the sheep eat a contaminated grass and ingest the eggs and the eggs hatches in the sheep bowel, the larval tapeworm burrows through the bowel wall and travel to the live by the blood vesicles. The Hydatid cysts develop in the liver, lung, brain or other organs. When dog eats the sheep viscera and ingest the Hydatid cyst, the protoscolices attaché to the small bowel wall and the worms begin to form proglottids, gravid proglottids, contains the eggs, detach from the end of the worm and spill their eggs into the lumen of the bowel. The eggs pass out in the faeces .Farm animal like cows and sheep become infected by eating the contaminated grass. Contaminated vegetables are the main reason in human infestations (8).


  1. John, David T. and William A. Petri. Markell and Voge’s Medical Parasitology. 9th ed. St. Louis, MI: Saunders Elsevier, 2006. 224-231.
  2. Mandell, Gerald L. Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, PA: Elsevier Inc., 2010. Ch. 290.  
  3. CDC. “Parasite Image Library: Echinococcosis.” DPDx. CDC, Web. 20 February 2010.
  4. Eckert, Johannes, and Peter Deplazes. “BioBerger SA, Marr JS. Human Parasitic Diseases Sourcebook. Jones and Bartlett Publishers: Sudbury, Massachusetts, 2006.
  5. Tappe, Dennis, August Stich, and Matthias Frosch. “Emergence of Polycystic Neotropical Echinococcosis.” Emerging Infectious Disease 14.2 (2008): 292-97. Web. 21 February 2010.
  6. Howorth, MB. “Echinococcosis of Bone.” Journal of Bone and Joint Surgery 27. (1945): 401-11. Web. 21 February 2010.
  7. Connolly, Stephanie. Echinococcosis. 2006. Web. 5 February 2010.
  8. M J Kumar, K Toe, R D Banerjee ; V 79, issue 928, Hydatid cyst of liver.

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