From the Guidelines

No treatment is required for a 5.5 cm hepatic cyst unless it becomes symptomatic.

Simple hepatic cysts are benign lesions that typically follow an indolent course without significant changes in size over time 1.
There is no indication for follow-up of simple hepatic cysts whatever the size, unless patients become symptomatic 1.
If a hepatic cyst becomes symptomatic, imaging (ultrasound first) will assess the size and look for complications and compression 1.

Symptomatic hepatic cysts can be treated surgically or with percutaneous aspiration sclerotherapy 1.
The recommended treatment for symptomatic simple hepatic cysts without biliary communication is the best locally available volume-reducing therapy, which can be either percutaneous aspiration sclerotherapy or cyst fenestration 1.
Aspiration sclerotherapy involves draining the cyst and temporarily exposing it to a sclerosing agent, such as 100% ethanol, 20% saline, tetracycline, or polidocanol 1.
Cyst fenestration procedures entail a laparoscopy, followed by drainage and resection of the extrahepatic cyst wall, and are associated with a low (<8%) recurrence rate 1.

From the Research

The management of a 5.5 cm hepatic cyst depends on whether the cyst is symptomatic or asymptomatic.

Asymptomatic simple hepatic cysts do not require treatment 2.
For symptomatic simple hepatic cysts, treatment options include:
- Percutaneous aspiration
- Aspiration followed by sclerotherapy
- Surgery, with laparoscopic fenestration being recommended by the American College of Gastroenterology clinical guidelines due to its high success rate and low invasiveness 2.
Other treatment options include:
- Unroofing and cyst drainage
- Cyst enucleation, which is proposed as the best surgical treatment due to the high recurrence rate associated with unroofing 3.
- Laparoscopic deroofing, which has been successfully used to treat simple benign liver cysts, even in cases with small biliary communication 4.
The choice of treatment should take into account the size of the cyst, the presence of symptoms, and the risk of complications such as infection, spontaneous hemorrhage, rupture, and external compression of the biliary tree or major vessels 2, 5, 6.

Ultrasound (US) is the most useful and noninvasive tool for diagnosis of simple hepatic cysts and can usually differentiate simple hepatic cysts from abscesses, hemangiomas, and malignancies 2.
Cysts with irregular walls, septations, calcifications, or daughter cysts on US should be evaluated with enhanced CT or MRI to differentiate simple hepatic cysts from cystic neoplasms or hydatid cysts 2.

Complications of simple hepatic cysts include infection, spontaneous hemorrhage, rupture, and external compression of the biliary tree or major vessels 2, 6.
Treatment of complications may involve aspiration/sclerotherapy, laparoscopic fenestration, or open liver resection, depending on the nature and severity of the complication 6.