Hepatic adenoma in pregnancy: A novel arterial embolization of hepatic adenoma in a pregnant patient

Abstract

A 31-year-old Caucasian female presented to the emergency department where a CT revealed a large right lobe liver mass found to be a hepatic adenoma. The patient ceased taking her oral contraceptives, but subsequently became pregnant. Serial ultrasounds revealed the adenoma was enlarging steadily throughout pregnancy, and the patient underwent a hepatic adenoma trans-arterial embolization at 33 weeks gestation to reduce the risk of bleeding in the third trimester and during labor. Embolization for treatment of a hepatic adenoma in a patient who is pregnant is a relatively novel approach to reducing the tumor size and reducing the bleeding risk associated with the third trimester of pregnancy. The patient had no postprocedure complications, and postprocedure imaging revealed the hepatic adenoma decreased in size with no further intervention required to date.

Introduction

Hepatic adenomas are the least prevalent of the benign liver tumors, accounting for approximately 0.001%-0.004% [1]. They are often found incidentally, more commonly in women with a history of prolonged oral contraceptive use [1]. Other risk factors include obesity, metabolic syndrome, and anabolic steroid use [2]. A dose-related risk ratio between oral contraceptives and hepatic adenoma has been previously demonstrated [3]. The European Association for the Study of the Liver guidelines [3] recommend resection or curative treatment for hepatic adenomas greater than 5cm (due to increased bleeding risk [1]) or tumors increasing in size ≥20% diameter. Symptomatic bleeding occurs in 14% of patients, with increasing risk as tumor diameter increases [2].

Hepatectomy is a common initial treatment for large hepatocellular adenomas, but literature more recently favors embolization due to decreased associated morbidity and mortality and shorter recovery time [2]. Bland embolization, hepatic arterial blockade using only small particles, is an effective treatment for reducing size of hepatic adenomas, as demonstrated by Crawford et al. [4] wherein 7 of 9 lesions (78%) decreased in size after embolization, with a median volume decrease of 67% [1]. Likewise, other studies have reported a decrease in tumor size ranging from 30% to 90% following embolization with none reporting tumor growth [1].

Though there are studies and case reports for arterial embolization as treatment for hepatic adenomas, there is little information on this treatment in pregnant patients. The procedure is frequently delayed until after pregnancy when possible due to the otherwise unavoidable radiation dose to the fetus. EASL guidelines state that prior to 24 weeks gestation, resection may be considered as an alternative to exposing the fetus to radiation, but after 24 weeks, trans-arterial embolization should be considered with large adenomas due to the increased risk of catastrophic bleeding as tumors may enlarge during pregnancy [3]. Review of the literature reveals a paucity of information on embolization of hepatic adenomas in pregnant patients. Here, we report the history of a pregnant patient with a steadily enlarging hepatic adenoma exceeding 5cm. The technique for bland trans-arterial embolization using polyvinyl alcohol particles of the hepatic adenoma in a pregnant patient is reported and discussed.

Case report

A 31-year-old Caucasian female presented to the emergency department with right upper quadrant pain consistent with cholecystitis. A CT scan discovered a 5.1cm X 4.0cm mass in segment 8 of the liver (Fig. 1). The patient underwent cholecystectomy and her RUQ symptoms resolved. A follow up MRI of the liver demonstrated a 5.4cm mass with heterogeneous enhancement and mild T2 hyper-intensity with features highly suggestive of a hepatic adenoma (Fig. 2). She had no evidence of active or previous bleeding from the lesion. The patient was notably on oral contraceptives (OCP's). The patient was treated conservatively with cessation of her OCPs and follow up imaging of the liver lesion. At 1-year post presentation the liver lesion had decreased to 4.5cm.

Fig. 1.

Axial (A) and coronal reformatted (B) contrast enhanced CT scan in the portal venous phase, showing a 5.1cm poorly enhancing mass (arrows) in segment 8 of the liver.

Fig. 2.

T2WI showing a lobulated mildly hyperintense 5.4cm mass (arrows) in segment 8 of the liver.

The patient became pregnant. She was closely monitored with serial liver ultrasounds of the mass at 4–6-week intervals to assess for enlargement, given the increased risk during pregnancy for growth and hemorrhage. The tumor was enlarging steadily throughout pregnancy reaching 6cm at 28-weeks gestation. Due to the size of the tumor and increased risk of hemorrhage in the third trimester, the patient was referred to interventional radiology for embolization at 33 weeks gestation after weighing risks and benefits of bleeding, open surgical techniques, and risks to the fetus including radiation exposure.

The procedure was performed via left radial artery access using standard techniques. A Jacky catheter (Terumo, Somerset, New Jersey, USA) was used to select the superior mesenteric artery, as there was noted to be a replaced right hepatic artery. A Renegade (Boston Scientific, Marlborough, Massachusetts, USA) high flow microcatheter was used to identify the right hepatic artery branch supplying the tumor and obtain super selective access to the branch feeding the tumor to minimize normal liver in the treatment zone (Fig. 3). Embolization was carried out with 300 um polyvinyl alcohol (PVA) particles to near stasis. Follow-up angiogram demonstrated pruning of the involved segment 8 branches and no tumor blush (Fig. 4).

Fig. 3.

Right hepatic artery angiogram demonstrating the feeding vessel (small arrows) to the adenoma (double arrowheads).

Fig. 4.

Postembolization arteriogram demonstrating pruning of the segment 8 branches and no tumor blush.

Radiation dose to the fetus was minimized using the lowest setting of pulse fluoroscopy available and taking care not to use fluoroscopy directly over the fetus. The patient had continuous fetal monitoring during and after the procedure provided by Obstetrics following preoperative consultation. No fetal abnormalities were noted during monitoring. There were no procedural complications.

Post procedure, the patient went on to deliver a healthy baby with no episodes of bleeding during the pregnancy or during labor. A follow up postprocedural liver CT was performed 8 months following embolization. The adenoma was less conspicuous and decreased in size at 8 months and 14 months postembolization with a maximum dimension of 3.3cm. Oral contraceptive pills were withheld, and surveillance imaging will be continued.

Discussion

The risk of bleeding from a hepatic adenoma increases in lesions greater than 5cm in diameter, such that historically, resection of the mass has been recommended [2]. However, minimally invasive treatments such as embolization and ablation of these masses are rising in popularity due to decreased morbidity and mortality compared to other treatment options [1]. Embolization for hepatic adenoma has been well-described, but there is little data about performing such a procedure in a pregnant patient. Ideally, hepatic adenoma embolization is performed outside of pregnancy due to the small, albeit real, maternal-fetal risks inherent in radiation-guided invasive procedures. However, with hormonal and physiological changes during pregnancy, hepatic adenomas may enlarge to the point where the risk of bleeding outweighs the risk of complication from surgery or a minimally invasive intervention, as was the case in this scenario. In our patient and others with hepatic adenomas that are increasing in size during pregnancy, the benefits of embolization may outweigh the risks, particularly using light conscious sedation and techniques to minimize fetal radiation dose. Our case is in line with the findings from Zhong et al. that trans-arterial embolization is safe and effective for the treatment of hepatic adenomas, and the tumor response rate is generally good [2]. Trans-arterial embolization may be a reasonable alternative to hepatic resection for hepatic adenomas demonstrating enlargement during pregnancy, potentially reducing treatment risk for the mother and fetus due to its minimally invasive technique. Using the trans-arterial embolization approach for treatment of a hepatic adenoma in a patient who is pregnant is a relatively novel approach to reducing the tumor size and reducing the bleeding risk in the third trimester of pregnancy and during labor. A multidisciplinary discussion with Interventional Radiology, Surgery, and Obstetrics with collaborative care is necessary in these complex patients to safely monitor and treat them through the gestational period.

Patient consent

The authors of this manuscript declare that an informed consent for publication of this case was obtained from the patient.