Liver Cysts

Question 1

A 50y/o male presents to his PCP with vague complaints of RUQ abdominal pain. A CT scan demonstrates a simple liver cyst. What is the proposed mechanism by which the cyst may cause this pain?

Answer 1

Stretching of Gleeson’s capsule for cysts near the liver capsule. Unclear if intra-hepatic cysts can cause pain symptoms.
– Rarely, infected cysts, spontaneous rupture, intracystic hemorrhage have been observed to cause pain.

Question 2

What are the characteristic findings of a simple liver cyst?

Answer 2

– well circumscribed, thin - almost imperceptible - walled, homogenous anechoic pattern. Houndsfield units c/w water.

Question 3

What are the typical characteristics of complex liver cysts?

Answer 3

Presence of septations, debris, mural nodules. Thick irregular wall with projections

Question 4

What is an advantage of CT in evaluating complex liver cysts?

Answer 4

The ability to detect enhancement of the cyst wall and evaluate projections or nodules (when compared with ultrasound).

Question 5

What are the particular advantage for MRI over CT scan in evaluating liver cysts?

Answer 5

Superior modality for evaluating small cysts <2cm and evaluating complexity in small cysts. Additionally, MRI can further characterize fluid to determine hemorrhage, mucinous, proteinaceous, etc… Also able to pick up wall irregularities imperceptible to CT scans

Question 6

When imaging is equivocal, what next step in diagnostic w/u is appropriate?

Answer 6

Aspiration of the cyst.

Question 7

After cyst fluid aspiration, what type of analysis should be done?

Answer 7

CEA, CA 19-9, bilirubin, cytologic analysis

Question 8

Based on cyst fluid analysis, simple liver cysts have what characteristics?

Answer 8

Thin, straw colored fluid. Acellular and w/o mucin. CEA, CA19-9, Tbil are negative or WNL.

Question 9

What are the therapeutic options to manage simple liver cysts?

Answer 9

1) Injection with sclerosant 2) Fenestration vs. marsupialization. Can be done laparoscopically. Operations usually reserved for large (>8cm) cysts or those that are clearly symptomatic.

Question 10

How are complex liver cysts managed?

Answer 10

Primary goal in work-up is to determine neoplastic potential. Most are cystadenomas or mucinous cystadenomas. Rarely, adenocarcinomas. MRI usually effective in determining etiology

Question 11

When imaging is equivocal with complex cysts, fluid analysis is crucial. What are the typical, concerning findings for neoplasm on cyst fluid analysis?

Answer 11

Thick mucinous and/or bloody fluid. Elevated CEA or CA 19-9 in fluid analysis.

Question 12

What therapeutic options are available for neoplastic cysts?

Answer 12

All require excision given the potential for malignant conversion or potential unidentified malignant components. Enucleation is usually all that is necessary. If cyst found to contain adenocarcinoma, formal resection may be required.

Question 13

Can metastatic colon cancer to the liver present as cystic lesions?

Answer 13

Yes. There is an entity called cystic degeneration of colon adenocarcinoma. This can occur - infrequently - in colon mets. Any patient with a h/o colon CA and a new finding of a liver cyst should be evaluated with this in mind.

Question 14

Echinococcus is a flat tapeworm whose life cycle alternates between carnivores(commonly -dogs) & herbivores (sheep/cattle). Human infections occur under what circumstances?

Answer 14

Consumption of contaminated vegetables. Contact with infected animals, their feces or infected soil.

Question 15

Echinococcus is endemic to what parts of the world?

Answer 15

Mediterranean countries, Middle & Far East as well as South America. The country with the largest experience in the literature is Turkey. However, given travel and immigration, the occurence is worldwide.

Question 16

Infection with echinococcus usually presents with a single cyst +/- 1-2 daughter cysts OR with multiple cysts throughout the liver?

Answer 16

A single large cyst with potentially 1-2 adjacent daughter cysts occurs in >80% of cases. This is c/w E. Granulosus infection. <20% are infected with E. Multilocularis and present with multiple small cysts throughout the liver.

Question 17

What are typical signs & symptoms of echinococcal cysts?

Answer 17

Usually assymptomatic for a prolonged period of time after infection. Cysts are slow growing. symptoms include RUQ abdominal pain, palpable mass, fever, fatigue, nausea and vomiting. Jaundice and cholangitis are somewhat rare and are concerning for rupture into the biliary system. With very large cysts, IVC compression and portal HTN have been described.

Question 18

What is the imaging modality of choice for echinococcal cysts?

Answer 18

Ultrasound. Two classification systems exist and are used throughout the world. U/S is the most cost effective worldwide as well.

CT/MRI are very useful - where available - to evaluate depth of liver invasion.

Question 19

Is there a role for ERCP in echinococcal disease?

Answer 19

Yes. Up to 25% of cysts have biliary communication with major ducts. Clearly indicated with jaundice or cholangitis. Use of ERCP in assymptomatic patients remains controversial. Some centers perform ERCP routinely for EC disease.

Question 20

What is the mainstay of antibiotic therapy in Echinococcal cysts? Duration?

Answer 20

• • Mebendazole or albendazole. Praziquantel is sometimes used in conjunction with mebendazole.
• • Antibiotics are “static” not “cidal” in this disease, so drainage is ALWAYS necessary.
• • Typical abx course is 1 week prior to drainage, followed by a four week course.

Question 21

Is percutaneous aspiration/drainage a viable option in this disease?

Answer 21

Yes. Usually done by U/S or CT guidance. Cysts are aspirated, then injected with antiparasitic agent, followed by reaspiration. Percutaneous aspiration, injection and reaspiration (PAIR) procedure.

Question 22

What are the indications/contraindications for the percutaneous (PAIR) procedure?

Answer 22

Clearly indicated for those who refuse surgery, multiple cysts(E.multilocularis dx.), or relapse post open surgery.

Contraindications: Cysts that are situated in a position that will not allow transhepatic drainage.

Question 23

What are the principles of open cystectomy?

Answer 23

1) Identify extent of cyst
2) Aspirate cyst fluid
3) Instill full volume with hypertonic saline(20%)
4) Aspirate the instilled volume
5) Unroof or excise all “free” sides of the cyst.
6) Cauterize the remaining cyst wall on the liver parenchyma side.
7) Identify and ligate any communicating duct (usually 1-2 ducts are present)
8) Inlay cavity with toungue of omentum

– Antibiotics continue for 28 days postop

Question 24

What are the principles of the “closed” technique for cystectomy?

Answer 24

1) Identify plane between liver and cyst and dissect whole cysts away en-bloc.
2) Obtain hemostasis with clips & cautery.
3) Critical to avoid spillage. Place HTS soaked lap pads to exclude the abdomen.
4) Identify & ligate any communicating duct.

– This technique is not practical with thin walled cysts.