Hydatid cyst of the liver, also known as echinococcosis, is caused by the larval stage of the Echinococcus tapeworm. Humans can become infected by ingesting tapeworm eggs from infected animal feces. The parasite then develops into a hydatid cyst in the liver or lungs. A hydatid cyst grows slowly and can reach a large size, sometimes replacing an entire liver lobe. It consists of an outer layer (ectocyst) and inner layer (endocyst) that produces cyst fluid and daughter cysts. Rupture of the cyst can lead to spread of the parasite within the abdomen or chest. Imaging such as ultrasound and CT are important for diagnosis and show cyst

1. Hydatid cyst of Liver
Uttam Laudari
MS First year
Department of General Surgery
KMCTH

2. Objective
• Introduction of H. Cyst
• Review of life cycle
• Pathology
• Fate of H. Cyst
• Investigations

3. Echinococcosis (hydatidosis, hydatid
disease)
• Zoonosis
• Organism- larval (metacestode) stages of cestodes (flat worms)
• genus -Echinococcus
• family -Taeniidae
• Definitve host-carnivores
• animals are both intermediate and definitive hosts
• Humans are the accidental intermediate host (dead end)

4. • The first North American case was observed in
1808 and published in 1822. The true nature of
the disease was not known until the second
half of the 19th century.

5. • There are three known forms of echinococcosis in humans:
• (i) cystic echinococcosis (hydatid disease) caused by
Echinococcus granulosus,
• (ii) alveolar echinococcosis (alveolar hydatid disease) caused
by Echinococcus multilocularis, and
• (iii) polycystic echinococcosis caused by Echinococcus vogeli
or Echinococcus oligarthus

7. Humans are an accidental, intermediate host and become infected when they
accidentally ingest eggs of the tapeworm
• The eggs hatch in the duodenum, and the released oncosphere penetrates
the mucosa and reaches a blood vessel
• most frequently settles in the liver and lungs
• the parasite develops its larval stage, the hydatid cyst, the clinical
presentation of E. granulosus
• The cyst is a chronic, well-localized, and adapted space-occupying
affliction that is not affected by the functional status of the host

10. Pathology
• By 21 days becomes visible with with naked eye
• Host tissue response- ecases parasite in fibous tissue
• Parasite responds by forming inert chitinous material
• 5 month- pericyst Avascular
Spaces within contains BV, Bile
ducts
integral part of both the liver
and the parasite
Difficult to remove
from liver

11. • Parasite can be separated by ectocyst
• H. cyst
– Unilocular
– Increases size about 1 to 1.5mm/month
– Fluid is under pressure
– Liters of fluid
Pathology

12. The fully developed wall of the cyst consists of
two layers
Ectocyst (laminated membrane)
• is a cuticular chitinous
structure without nuclei
• never grows thicker than 5
mm, regardless of cyst size.
Endocyst (germinative )
• microscopic dimensions
• responsible for the
production of the
– crystal-clear hydatid fluid
– ectocyst
– brood capsules
– scoleces
– the daughter cysts
Pathology

13. Pathology

14. • Daughter cyst formation is considered a defense reaction  Endogenic
vesiculation
• Daughter cysts are true replicas of the mother cyst.
• The presence of daughter cysts is a problem for chemotherapy,
protoscolicide activity, and the standard PAIR procedure
Ectogenic vesiculation of E. granulosus is infrequent.
• It occurs when there is a small rupture or defect in the ectocyst and the
endocyst passes through
Pathology

15. • Hydatid fluid is antigenic
• This antigenicity is rarely of great clinical significance
• Allergic reactions range from skin rash to a frank anaphylactic
reaction
• The antigenicity of hydatid fluid is the basis of serodiagnostics
Pathology

16. Clinical Presentation of Liver Hydatid
Cysts
• depend on the site, size, number, vitality, and stage of
development of the cyst.
• Simple, uncomplicated liver hydatid cysts usually
asymptomatic or present with nonspecific symptoms
• Complicated liver hydatid cysts cause specific symptoms and
signs

17. Clinical Presentation

18. Suppuration and Secondary Bacterial
Infection
• most frequent cause of infection is a cystobiliary
communication
• Clinically presents at pyogenic liver abscess
• An infected hydatid cyst undergoes structural changes and the
parasite dies
• incidence in the literature ranges from 11.0% to 27.1

19. Pressure Effects
• grow in the direction of the least resistance
• Pressure effects appear sooner or later
• symptoms result from direct pressure or distortion of
neighboring structures or viscera.
• An enlarging cyst
– atrophy of surrounding hepatocytes
– fibrosis
– compensatory hypertrophy of the remaining liver parenchyma
– replaces an entire liver lobe

20. • Serious consequence of cyst enlargement
Rupture
• Three types of cyst rupture have been addressed:
– obscure
– free
– communicant rupture

21. Obscure (Internal) Rupture
Injury or penetration of bile between pericyst and ectocyst
Ruptue of ectocyst
Protoscolesces occupies spaces
Develops 100s of daughter cyst
Unilocular  multilocular

22. Such multilocular cyst when surgically opened
No ectocyst
Floating 100s of daughter cyst
Within yellow fluid of gelatin like amorphous mass inside
pericyst
Obscure Rupture

24. Clinical significance of multivesicular cysts
• host is exposed to hydatid antigens in the hydatid fluid
• cyst is bacteriologically sterile
• cyst contents cannot be easily aspirated and needs to be
scooped out
• the cyst must be treated as viable and infective
• bile stained cyst contents mandates a meticulous search for
CBC
Obscure Rupture

25. Not all multivesicular cysts have bile-stained fluid,
and not all
cysts with bile-stained fluid have active communications with the
bile ducts
Obscure Rupture

26. hydatosis

27. Free Rupture
In free rupture, the hydatid contents disseminates throughout the
peritoneal or pleural cavity

28. Intraperitoneal Rupture
• Hydatid cyst grows in the direction of the least resistance
• superficial portion of the pericyst is stretched, thinned out
• cyst irregularly shaped, fibrous whitish structure
protruding from normal liver parenchyma
• Cysts reaching the anterior and inferior part of the liver
continue to grow, protruding into the abdominal cavity
• high intracystic pressure causes rupture
of both univesicular and multivesicular
cysts

29. Clinical presentations of intraperitoneal rupture
• (i) In acute symptomatic rupture,
– peritoneal irritation and acute abdominal symptoms occur
– The incidence is about 1% to 4%.
• (ii) In anaphylactic shock
– rupture precipitates severe circulatory collapse, which
may be fatal mask the abdominal manifestations
• (iii) In silent rupture, the patient presents with disseminated
abdominal hydatidosis, unaware when the rupture occurred

30. (iv) Herniation of the laminated membrane occurs through the adventitial
pericyst
The herniating membrane does not actually burst and therefore no spillage
of hydatid debris occurs
The initial liver cyst remains small
although the
herniated, extrahepatic portion of the cyst can attain a volume of several
liters
– This condition mimics ascites, and attempts at percutaneous aspiration
can lead to allergic manifestations
Intraperitoneal Rupture

31. • Intraperitoneal rupture is a life-threatening complication that
results in secondary echinococcosis
• •Multiple cysts develop throughout the peritoneal cavity
causing
– intestinal obstruction,
– gross abdominal distention,
– ascites,
– and cachexia several years after the rupture.
• This is the secondary, smaller life cycle for the parasite,
occurring only in the intermediate host.
Intraperitoneal Rupture

32. Intrathoracic Rupture
• Elevated hemidiaphragm and a sterile sympathetic pleural effusion can
be the first signs of liver hydatid disease
• Upward extension of a subdiaphragmatic cyst is usually asymptomatic,
although it can cause dry cough, dyspnea, chest pain, and toxemia
• The pleura and adherent basal lung segments often become inflamed
and indurated
• Frank intrapleural rupture with empyema (hydatopiothorax) is rare
• pneumonitis or lung abscess

33. • The hydatid cyst may erode into a bronchiole and the contents
can be evacuated
• Rupture into bronchiole daughter cysts in the sputum
• Ocassionally a bronchobiliary fistula will arise
Expectoration of bile-tinged sputum
• The incidence of diaphragmatic or transdiaphragmatic
thoracic involvement by hydatid cysts in the dome of the liver
ranges from 0.6% to 16%
Intrathoracic Rupture

34. Communicant Rupture
Hydatid cysts can rupture into physiologic
channels (e.g., biliary, blood vessels) or
adjacent organs (e.g., digestive tract)

36. • In silent rupture, bile leaks from eroded small ducts into the
cyst, causing
– endogenic vesiculation
– suppuration
– eventually death of the parasite
• Such cysts are filled with bile-stained detritus, although no
visible bile duct communications can be seen.
• Probably 80% to 90% of hydatid cyst bile duct ruptures are of
the silent type.
Communicant Rupture

37. • A triad of symptoms characterizes rupture into the bile ducts:
I. biliary colic
II. partial intermittent or complete ductal obstruction with
cholangitis and jaundice
III. germinative membranes in the feces.
Communicant Rupture

38. • The rapid discharge of the cyst contents into a major bile duct or
body cavity can lead to the sudden absorption of the hydatid antigen
in a sensitized patient, resulting in anaphylaxis.
• More frequently, pruritus or urticarial rash is the major external
manifestation.
Episodes of asthma have been reported.
Communicant Rupture

39. Organ Imaging in the Diagnosis and Treatment
of Hydatid Disease
•X-ray
• Limited value
• In endemic areas, elevation of the right hemidiaphragm in an
otherwise healthy, asymptomatic patient is highly indicative of
liver hydatidosis
• Sometimes streaklike or round calcification of a senile hydatid
cyst.

41. Ultrasound Imaging
• readily available and easy to master
• comparatively cheap, noninvasive, enables
interventional procedures

42. • Pathognomonic US diagnostic features are
I. unmistakable daughter cysts (rosettes•) within the main cyst
cavity
II. detachment of the membrane of the cyst (double-contoured
membrane)
III. agglomeration of daughter cysts in the dependent portion of a
hydatid cyst
IV. calcification of the cyst wall
Ultrasound Imaging

43. • Based on US signs, Hassen Gharbi in 1981 classified liver
hydatid cysts into five types
I. pure fluid collection
II. fluid collection with a split wall
III. fluid collection with septa
IV. heterogeneous appearance, and
V. reflecting thick walls
– Gharbi cyst types II and III as well as type V calcified cysts
are characteristic for liver cystic hydatid disease.
Ultrasound Imaging

45. Unilocular,no cyst
wall
Hydatid sand
rossette
Waterlily sign
calcification
Degenerative contents

46. 1/3rd sterile 2/3rd fertile
½ secndry cyst
Wait and watch
Further differential
diagnosis
Chemotherapy
Surgery
PAIR
Chemotherapy
Active cysts (type CL, CE 1, CE 2)
No cyst wall
Hydatid sand
rossette
Management options

47. living protoscoleces can exist
and
all treatment options should be considered
Irregular wavy nature of
fluid level produced by
collapsed hydatid
membrane floating on top
of residual hydatid fluid
Degenerating (transitional state) cysts (type CE 3)

48. further differential diagnosis is frequently
Required
Inactive cysts (type CE 4 and CE 5),

49. CT Scan
• CT yields the most accurate information regarding the number,
position, and cyst characteristics as well as the extent of intra-
abdominal disease.
• Discontinuity of the cyst wall in the vicinity of bile ducts is
highly suggestive of CBC

50. ERCP
• ERCP has little value in asymptomatic patients and
should be avoided
• Indications for endoscopic papillotomy in the
preoperative period are
1. when US, CT, or ERCP detect hydatid material in the
CBD
2. when cholangitis has been a feature of the clinical
presentation, regardless whether a CBC is detected

51. indications for endoscopic papillotomy in the
postoperative period are
1. hydatid material in the CBD
2. a biliary fistula lasting longer than 3 weeks
3. high-output biliary fistula (more than 1,000 mL per 24 hours)
4. Jaundice
5. short stricture obstructing the papilla
Critical use of ERCP and papillotomy in patients with CBC has reduced
mortality and in-hospital stay

52. References
• Mastery of surgery
• Sabiston text book of surgery
• Schwartz text book of surgery

53. Next presentation on..
• Medical Management
• Minimally Invasive techniques (PAIR)
• Various Surgical Modalities of management

54. Thank you