TAE Combined with Microwave Ablation in the Treatment of Rare Giant Hepatic Hemangioma:Case Report and Literature Review

Background: hepatic hemangioma is the most common benign tumor of the liver. However, patients with large hemangiomas that cause compression symptoms or that are at risk of rupture may need further intervention. It is necessary to explore additional minimally invasive and personalized treatment options. Case presentation: A 47-year-old female was diagnosed with right hepatic hemangioma for more than 10 years. Abdominal contrast-enhanced CT and CEUS revealed that there was a large hemangioma in the right liver, with a size of approximately 95x97x117 mm. Due to the patient's refusal of surgical treatment, hepatic artery embolization was performed in the rst stage, then after 25 days of liver protection treatment, the liver function indexes decreased to normal levels. Then, B-ultrasound-guided microwave ablation of the giant hepatic hemangioma was performed. Ten days after the surgery, hepatobiliary ultrasonography showed that the hemangioma of the right liver was smaller than the previous size (the volume was reduced by approximately 30%). Then the patient was discharged from the hospital, and CT suggested that the hepatic hemangioma is signicantly smaller two months after discharge. Because of COVID-19, the patient's CT examination was delayed. Conclusions: TAE combined with microwave ablation is a safe and effective minimally invasive treatment for hepatic hemangioma.

A 47-year-old woman complained that the physical examination found hemangioma for more than 10 years, had a history of caesarean section and unilateral salpingectomy and had failed interventional hepatic artery embolization at local hospital. CT examination with an abdominal contrast-enhanced CT showed the following: the right lobe of the liver had a low-density mass with a size of approximately 95 × 97 × 117 mm, the boundary was clear, the density was uniform, suggested a right hepatic hemangioma, (Fig. 1). Ultrasound angiography showed that the right posterior hepatic lobe displayed a strong echogenic area with a size of 95 × 97 × 117 mm, and the boundary was still clear. A total of 2.4 ml of sulfur hexa uoride microbubble solution was injected through the anterior elbow vein, showing a small amount of enhancement around the arterial phase in the strong echo zone. During this period, the contrast agent was signi cantly lled. Contrast-enhanced ultrasound showed right hepatic posterior hemangiomas (Fig. 2).
However, the patient refused surgical treatment., the patient was strongly encouraged to undergo microwave ablation due to the consideration of large local lesions as well as to protect the surrounding important blood vessels, to ensure the scope of ablation, to reduce intraoperative bleeding caused by puncture and ablation. The detailed plan according to the location and size of the lesion was as follows: one-stage hepatic artery interventional embolization, followed by short-term B-ultrasound-guided microwave ablation of hepatic giant hemangioma.
Intraoperatively, the patient was placed in the supine position and covered with a perineal routine disinfection drape. Right groin local anesthesia (2% lidocaine) was administered. The femoral artery was punctured, followed by placement of a sheath and an intrathecal heparin water-sealed tube, and then intrathecal 5-Fr angiography was performed. A catheter was inserted for celiac artery angiography, which showed that the hepatic artery was signi cantly thickened and tortuous, and a large mass-like abnormal staining area was seen in the right liver (Fig. 3A, B). Microcatheters and micro-guidewires were introduced into the right hepatic artery from the contrast catheter, and the micro-guidewire was withdrawn. Then, 10 mg dexamethasone and 8 mg ondansetron were perfused, and the microcatheter and micro-guidewire were superselected to the right lobe of the liver. In the small branch, angiography was performed to determine the supply of the blood vessels. Under uoroscopy, the microcatheter was injected slowly with 20 ml iodized oil + 15,000 units bleomycin + a small amount of contrast medium mixture, and then a small amount of gelatin sponge was injected into the blood vessels in the main supply vessels. There was mild re ux, and angiography showed that the abnormal staining area of the liver had disappeared (Fig. 3C). The patient had no obvious discomfort, and the catheter was withdrawn. The sheath was removed after surgery, the puncture site was pressure-bandaged, the sandbag was pressed to stop the bleeding, and the patient was placed in a supine position for 24 hours. The side was continuously pressed for 8 hours. In terms of the postoperative monitoring of vital signs, there were no complaints of discomfort, no transient fever, and a maximum body temperature of 38 °C; routine blood tests showed a white blood cell count of 13.3 × 10 ^ 9 / L, 87.4% central granulocytes, and increased liver function indicators (ALT 105 U / L, AST 74 U /L, r-GT 74 U/L). Postoperative prophylactic antibiotics and liver protection treatment were administered. Two days later, routine blood examination showed that the white blood cell levels decreased to normal, and the liver function indicators were normal (ALT 105 U/L, AST 74 U/L, r-GT 76 U/L), so liver protection treatment was continued.
After 25 days, the liver function index decreased (ALT 61 U/L, AST 24 U/L, r-GT 164 U/L), and Bultrasound-guided microwave ablation of hepatic hemangioma was carried out. The patient was placed in a supine position, general anesthesia was administered, and routine surgery and disinfection of the surgical eld were carried out; for ultrasonic positioning, an 11-point blade with a 2 mm small mouth was positioned on the skin, avoiding color Doppler blood ow, and two 15 G needles were punctured into the right posterior hepatic lobe for real-time ultrasound-guided microwave ablation. The following procedures were used for the lesions: N1: Right lower hepatic lobe lesion in the lower front, energy: 55 Wx600 s; N2: Right posterior hepatic lobe lesion in the posterior segment, energy: 55 Wx600 s ( Hepatobiliary ultrasonography 10 days after the operation showed that the posterior lobe of the right liver had a strong echo region with a size of 71 × 66 × 58 mm and a relatively clear boundary, and the hemangioma in the right liver decreased in size compared with the previous size (approximately 30% smaller in volume) (Fig. 5A), Then the patient was discharged from the hospital, CT 2 months after discharge showed a right lamellar hepatic mass with a high-density shadow after microwave ablation of the hepatic hemangioma (Fig. 5B). Because of COVID-19, the patient's CT re-examination was delayed.

Discussion
The incidence of hepatic hemangioma is 0.4%~20.0% [8] , and the autopsy discovery rate is 0.4%~7.3% [9] .Hepatic hemangioma mostly grows slowly and has no tendency to become malignant; additionally, spontaneous rupture is rare. Some scholars abroad have classi ed large hemangiomas as those > 5 cm in diameter. Most hepatic hemangiomas do not require treatment or only need regular follow-up. However, giant hemangiomas larger than 5 cm in diameter may cause compression symptoms, such as obstructive jaundice, gastric outlet obstruction, and Budd-Chiari syndrome, or coagulopathy (Kasabach-Merritt syndrome) requiring further intervention [10] . The current treatments include surgery, interventional therapy [3] , radiofrequency and microwave ablation [4] .
TAE is a common method used for the treatment of hepatic hemangioma. Most of the larger hepatic hemangiomas requiring clinical treatment have a multi-arterial blood supply. Some arteries that are a part of this blood supply are not easily found during angiography, and collateral circulation easily forms after embolization of these artery, resulting in recurrence of hepatic hemangioma. If the tumor is over-embedded, it may cause serious complications such as abnormal liver function, intrahepatic bile duct injury or ectopic embolism. Therefore, TAE is often used as an adjunct therapy or alternative [3] . For large (5-10 cm), symptomatic hepatic hemangiomas the safety and effect of microwave ablation have not been fully con rmed [5] . The patient had previously undergone TAE treatment for hepatic hemangioma, but the effect was dissatis ed. The hepatic hemangioma was more than 10 cm in size, and the surgical trauma was substantial. Simple TAE or microwave and radiofrequency treatments may not meet the treatment needs.
Microwaves have a higher thermal e ciency than radiofrequency ablation [11] .This is mainly due to the different ways in which microwaves and radiofrequencies interact with tissues. The heat-generating component of radiofrequency ablation is mainly located within a few millimeters around the electrode and is susceptible to tissue carbonization. The expansion of the solidi cation range mainly depends on conduction heat dissipation, while microwaves have a certain penetrating power in the tissue, their heating range is large, and they are subject to the impact of carbonization, which is small. Since microwaves have a higher tissue solidi cation temperature than radiofrequencies, they have a strong coagulation ability in blood vessels, and their coagulation volume and shape are less affected by blood vessels; thus, microwave ablation has a larger ablation range, more easily resulting in intratumor ablation. The su ciently high temperature for ensuring a large ablation range through heat transfer re ects the higher thermal e ciency of microwave ablation. The volume of microwave ablation is larger than that of radiofrequency ablation, which can reduce the number of punctures and the incidence of complications. For tumors with a diameter ≥ 5 cm, microwave ablation can be combined with multiple needles to signi cantly expand the ablation volume. Therefore, for large tumors, microwave ablation is more advantageous than radiofrequency ablation. [12] Microwave ablation is also less affected by blood perfusion. It is more suitable for treating tumors adjacent to large blood vessels. Multiple needles do not interfere with each other at the same time during ablation, and they have a synergistic effect, thereby making the ablation range larger and the ablation time shorter [13] .
We decided to adopt microwave ablation combined with TAE treatment. The safety and e cacy of microwave ablation combined with TAE treatment is better than those of ablation alone [14] . The reasons are as follows: (1) TAE can effectively reduce the blood supply in the tumor by embolizing the blood vessels of the hemangioma, which can reduce the heat taken away by the "heat sedimentation effect" caused by the rich blood ow during the ablation process, resulting in a large microwave ablation treatment e ciency; (2) after TAE blocks the artery supplying the hemangioma, it can effectively reduce the risk of intraoperative bleeding; and (3) the application of iodized oil to the tumor in the TAE procedure can further de ne the hemangioma boundary and accurately locate it to avoid damage to the surrounding organs [15] . Of course, the optimal interval and the choice of vascular sealing materials during TAE treatment require further research and demonstration.
The main complications of ablation are hemorrhage, important organ puncture injuries, and organ thermal injuries, such as pleura, diaphragm, and lung injuries. Hemolysis-related complications, such as anemia, jaundice, hemoglobinuria and temporary kidney injury, and even severe cases, lead to acute renal failure [16] . To reduce the risk of ablation and puncture, we believe that the puncture process should pass through more normal liver tissue as much as possible to reduce the risk of bleeding; furthermore, precise needle insertion, avoidance of repeated puncture, and utilizing the safety distance from "high-risk organs" when placing needles should be implemented. To avoid thermal damage, the needle should be ablated to prevent bleeding when withdrawing the needle; to avoid the excessive volume of single ablation, adequate rehydration should be administered during the perioperative period, especially during surgery, and if necessary, alkalinized urine should be implemented to avoid acute kidney injury or even renal failure. Complete ablation of the tumor should not be excessively pursued in order to avoid causing excessive side damage; if necessary, the tumor can be ablated once the puncture causes bleeding.
Feasible local ablation of the tumor can be carried out while considering conservative treatment, including hepatic artery embolization and surgical hemostasis.

Conclusions
After slight treatment with TAE combined with ablation, the hemangioma was mostly necrotic, and the volume was signi cantly reduced; at the very least, the tumor will not continue to grow rapidly and affect liver function, in line with the therapeutic purposes and concepts of benign liver tumors. TAE combined with microwave ablation is a safe and effective minimally invasive treatment for hepatic hemangioma.

Declarations
Ethics approval and consent to participate The study protocols were approved by the Ethical Committee of the Taizhou Central Hospital.

Consent for publication
Written informed consent was obtained from the patient for publication of this article. A copy of the written consent is available for review by the Editor of this journal.

Availability of data and materials
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. Figure 1 CT suggested a right hepatic hemangioma, 1A: Plain, 1B arterial phase, 1C : venous phase.

Figure 2
Ultrasound angiography showed that the right posterior hepatic lobe displayed a strong echogenic area with a size of 95x97x117 mm.  Partial images of radiofrequency ablation guided by B-ultrasound.

Figure 5
Results of B-ultrasound and CT reexamination after operation.