We were able to discuss the differential for solitary liver lesions, features on ultrasound that are concerning for complex cysts, discussion of radiologic features c/w various lesions, and Rabih Geha’s fabulous teaching on polycystic liver disease.
Here are the pearls:
Differential of Liver Cysts
We discussed the differential of solitary liver lesions, however, here let’s focus on the specific differential for cystic liver lesions. You can think about this as differential by splitting it into two categories: simple cysts vs. complex cysts. Simple cysts appearing as fluid-containing lesions (anechoic) without any evidence of complex internal features (internal septations, calcification, nodularity, wall thickening/irregularity, hemorrhagic/proteinaceous contents). Complex cyst contain one or more of the complex internal features above.
- Simple cysts
- Simple primary hepatic cysts (benign developmental hepatic cyst)
- Bile duct hamartoma (von Meyenburg complex)
- Polycystic liver disease
- Caroli disease
- Rare autosomal-recessive disorder characterized by multifocal saccular dilation of the intrahepatic bile ducts
- Complex cysts
- Primary: biliary cystadenoma or cystadenocarcinoma, squamous cell carcinoma
- Secondary: cystic metastases
- HCC (would be atypical presentation)
- Echinococcal cyst (hydatid cyst)
- Traumatic intrahepatic hemorrhagic/infarction
The Importance of Imaging
Here is a table with characteristic features of liver cysts pilfered from the Radiology journal.
|Ultrasound||CT||MRI||Pattern of contrast enhancement|
|Simple hepatic cyst||-Anechoic
|-Homogenous (low intensity on TI, high intensity on T2)||None|
|-Homogenous (low intensity on TI, high intensity on T2)||Wall enhancement|
|Echinococcal (hydatid) cyst||-Internal septations +/-daughter cysts
-+/- daughter cysts
|-Hypointense rim on T1 and T2||Wall may enhance|
|Polycystic liver disease||Innumerable simple cysts||Innumerable simple cysts||-Homogenous (low intensity on TI, high intensity on T2)||None|
Polycystic Liver Disease
Attached is a review on autosomal dominant polycystic liver disease courtesy of Rabih. Here are the CliffsNotes:
- Autosomal dominant polycystic liver disease (ADPLD) can exist as a separate entitiy as well as in conjunction with autosomal dominant polycystic kidney disease (ADPKD).
- ADPLD presents with multiple cysts that are large, variable in size, and can present within the liver parenchyma but not in contact with the portal triad or be adjacent to the portal triad.
- There is an age-dependent increase in the frequency of hepatic cysts in patients with ADPKD-associated ADPLD (20% in third decade à 75% by the seventh decade).
- Women with ADPKD are more likely to have larger liver cysts and have more cysts than men.
- Exposure to estrogen increases the likelihood for liver cysts in patients with ADPKD-associated ADPLD.
- There is an association with vascular malformations in patients with isolated ADPLD namely cerebral aneurysm and aortic root dilation though causality has not been proven.
- As was the case with the patient presented today, patients are often asymptomatic and once they develop symptoms these are usually secondary to mass effect from the cysts on nearby anatomic structures.