COMMENTARY

Imaging Found a Focal Liver Lesion--Now What?

David A. Johnson, MD

Disclosures

February 23, 2018

More Imaging, More Questions

Hello. I am Dr David Johnson, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia.

Welcome back to another installment of GI Common Concerns, in which we discuss matters that we routinely see in our practices. Today's discussion is on focal liver lesions.

We routinely order various imaging in our practices, be it for screening, surveillance, or other reasons. It is not unusual for these diagnostics to reveal what may be a focal liver lesion. This is especially true given the number of CT and MRI scans performed in this country, which have increased over the past decade. We're also seeing a variety of things picked up by ultrasound.

What do we do with these focal liver lesions? The American College of Gastroenterology (ACG) provided excellent guidance on this issue.[1] Let me take you through some of the highlights.

Suspected HCC in Solid Lesions

Once identified, the first question to ask is whether the lesion raises concerns about a diagnosis of hepatocellular carcinoma (HCC). To determine this, we must begin by taking a detailed history and physical examination, understanding which medications a patient is taking, and then beginning to say whether [the lesion] is solid or cystic.

In a solid lesion with risk factors for HCC, the ACG recommends you perform MRI or CT for lesions > 1 cm. When you request this, you want to do dynamic triple-phase CT: a late arterial phase, a portal venous phase, and a delayed venous phase. This is a very important strategy to rule out HCC.

Because MRI can do this as well, there has been some question as to which modality is better. This was the topic of a just-published systematic review and meta-analysis, which was commissioned by the American Association for the Study of Liver Diseases.[2] After looking at all of the studies comparing CT with extracellular contrast-enhanced MRI or gadoxetate-enhanced MRI in adults with cirrhosis and suspected HCC, they concluded there was no reason to suspect one is better than the other.

There are circumstances where one may be better for the individual patient. MRI doesn't do as well in patients who have large-volume ascites, those who are claustrophobic (obviously), or those with breath-holding abnormalities.

Certainly, local expertise also makes a difference, and this review[2] reported a slight trend in favor of MRI, so there was a bit of publication bias toward the academic centers.

We also have to consider what is good for the patient on the basis of certain characteristics, and recognize that contrast may be a problem. This is pointed out nicely in the recent review,[2] that if patients have mild to moderate renal insufficiency, it is perhaps best to avoid contrast agent for CT and to defer to the MRI. If patients are dialysis-dependent, then it becomes very important to avoid MRI contrast. There is a condition known as "nephrogenic systemic fibrosis," which can be a catastrophic event. This may be a little bit safer with some newer contrast agents with gadolinium (eg, gadobenate dimeglumine). Regardless, in such cases you should talk to your nephrologist, because dialysis patients probably should not have the MRI contrast at present.

If you have a suspect for HCC, the radiologist should be able to tell you yea or nay. The sensitivity and specificity of the diagnostics for HCC are quite strong. In fact, transplant candidacy now does not require a liver biopsy to determine whether HCC is present, but instead relies on radiologic diagnosis; the exception are patients in whom status cannot be determined otherwise. The risk for bleeding and for tumor seeding are a problem when you start doing percutaneous biopsies.

Suspected Focal Nodular Hyperplasia

If it's not a solid lesion for which you're concerned about HCC, more often than not these are discovered to be what we call "incidentalomas"—that is, a suspect benign lesion. Again, dynamic triple-phase CT or MRI is very helpful.

You may find that these patients have a characteristic central scar called "focal nodular hyperplasia." These are benign conditions. They don't routinely require patients to have continued monitoring unless there is some clinical circumstance warranting that. However, the ACG's guideline suggests that if the patient is going to remain on oral contraceptives, they should be monitored. That doesn't quite make sense to me, because they don't note that there is an association with oral contraceptives.

Suspected Hepatocellular Adenoma

The next point the guidelines touch on is solid lesions is hepatocellular adenoma. These are benign lesions that have been associated with oral contraceptives, hormone-containing intrauterine devices, and anabolic steroids, which should all be considered for discontinuation. Pregnancy is not absolutely contraindicated but should be taken on a case-by-case basis.

Patients with hepatic adenoma do not need to have surgery or resection, with the exception being if it gets to ≥ 5 cm, which tends to have a risk for rupture or other consequences. Surgical referral to a center of expertise is recommended at that point.

These patients should be monitored at 6- to 12-month intervals, and certainly until there is some stability.

Suspected Hemangioma and Nonsolid Lesions

There are the other solid areas that look more vascular; these are the hepatic hemangiomas, which we see somewhat frequently. You can expect anywhere around 5%-7% of patients undergoing imaging to have hemangiomas. These are easily confirmed with an MRI or dynamic CT scan. They do not warrant further evaluation or intervention, given the low risk for rupture. They certainly don't warrant a biopsy.

For suspected simple hepatic cysts, you need to identify them on ultrasound for such characteristics as septations, calcifications, daughter cysts, and walls within the cyst. If [any of these characteristics is present], they need to be categorized as a complex cyst.

Then the question is whether it is symptomatic or asymptomatic. If you have a noncomplex, asymptomatic cyst, there really is no recommendation to do anything other than observe it. They do not need follow-up, needle puncture, or aspiration.

If you have a symptomatic lesion, they should be investigated further. This can involve systematic evaluation with needle aspiration, but you want to make sure they are not hydatid cysts, which if punctured can result in an anaphylactic reaction. Certainly, if there is a complex cyst that is symptomatic and a suspect for abscess, this is a whole different management strategy as well.

Only very rarely do cysts become symptomatic or require cyst aspiration. They can be aspirated, but they tend to recur right away. Sometimes large symptomatic cysts compress on the capsule, which needs to be marsupialized by a surgeon. Such an occurrence would be the exception, and it requires you to get involved with a surgeon who has performed these types of procedures.

Take-Away Messages

We routinely see focal lesions of the liver. When determining the diagnostic imaging strategy you'll use, consider the indications. If you think HCC may be in play, obtain triple-phase CT or MRI. And don't forget to avoid gadolinium in the dialysis patient, because the concern for nephrogenic systemic fibrosis is a real one. Also, take into account local expertise.

For the so-called incidentalomas, determine whether they are solid or cystic. For solid lesions, we return to the use of triple-phase CT or MRI. These patients have a characteristic central scar to look out for. For hepatic adenoma, the recommendation is to monitor as appropriate.

For the cystic lesions, the question is whether they are symptomatic or asymptomatic. Here too, it's much more common for us to just observe them.

I did not mention polycystic liver disease, which is also very rare. Large lesions can require systematic evacuation of the cysts, again owing to pressure. It's important to speak to somebody with experience in these. This is not a standard radiologic procedure. You may want to have these patients seen in a center of excellence.

Given the large range of incidentalomas and real things we see on focal lesions of the liver, hopefully this presentation has provided you with a little more direction in your next intervention with a patient.

I am Dr David Johnson. Thanks again for listening. I hope you found this helpful.

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