Efficacy and safety of thermal ablation for large hepatic caudate lobe hemangioma

Abstract

BACKGROUND

For large hepatic hemangiomas in the caudate lobe, surgical resection is difficult and risky; a clinical gap remains in effective minimally invasive alternatives.

AIM

To investigate the safety and efficacy of thermal ablation for hepatic caudate lobe hemangioma.

METHODS

This retrospective single-arm study enrolled 16 patients with 16 large hepatic caudate lobe hemangiomas treated by thermal ablation from April 2017 to January 2025. Safety and efficacy were evaluated. Six Spiegel lobe lesions underwent laparoscopic microwave ablation (MWA), two with intratumoral resection after MWA-induced coagulation. Three caudate process lesions received computed tomography-guided radiofrequency ablation (CT-RFA). Of seven paracaval lesions, five underwent laparoscopic MWA and two CT-RFA.

RESULTS

The technical success and radiologic response were achieved in all 16 patients (100%). All 5 symptomatic patients achieved symptom relief. No major complications occurred; minor events (Society of Interventional Radiology class A) included self-limited postoperative fever (n = 2) and transient hemoglobinuria (n = 1), all resolving within 72 hours. The median ablation time was 113 min [interquartile range (IQR): 30-135]. The median intraoperative blood loss was 10 mL (IQR: 0-23). No patient received blood transfusions during or after the operation. The median postoperative hospital stay was 3 days (IQR: 2-4). The complete ablation rate was 86%. At a median follow-up of 21 months (IQR: 15-33), no tumor progression or recurrence was observed. The mean diameter of the ablated zone decreased significantly.

CONCLUSION

With an integrated strategy, thermal ablation for hepatic caudate lobe hemangiomas is a safe, feasible, and effective minimally invasive therapeutic modality.

Key Words: Ablation techniques; Hepatic hemangioma; Caudate lobe; Laparoscopic intratumoral resection facilitated by coagulation; Treatment outcome

Core Tip: Thermal ablation using an integrated strategy (laparoscopic and computed tomography-guided approaches with microwave or radiofrequency ablation) is a safe, feasible, and effective minimally invasive treatment for large hepatic caudate lobe hemangiomas, achieving 100% technical success and clinical response rates with only minor, self-limited adverse events.

INTRODUCTION

Hepatic hemangioma is the most common benign tumor of the liver, with a reported incidence of 3%-20% in the general population[1]. While the vast majority of hemangiomas are asymptomatic and require no intervention, those accompanied by clinical symptoms or progressive enlargement may necessitate active management[2].

Traditionally, the gold-standard treatment for hepatic hemangioma was surgical resection. However, given the caudate lobe’s proximity to major vessels and the main hepatic ducts near the second hepatic hilum, along with its deep-seated position and limited exposure, the operative field is severely constrained, and intraoperative blood loss control is difficult. Resection in such areas is associated with considerable technical difficulty and a substantial increase in perioperative morbidity[3,4].

Recent studies have demonstrated that thermal ablation therapies, represented by radiofrequency ablation (RFA) and microwave ablation (MWA), are safe, feasible, and effective for treating hepatic hemangioma[5,6]. Caudate lobe hemangioma of the liver is relatively rare; there is limited research on the application of thermal ablation specifically for hepatic caudate lobe hemangiomas[7].

To address this knowledge gap, we conducted a single-center, retrospective study of patients with caudate lobe hemangiomas treated with thermal ablation. Based on the specific location of the tumors, an integrated thermal ablation strategy was applied[8,9].

Therefore, this study aimed to preliminarily evaluate the safety and efficacy of this integrated thermal ablation strategy in the treatment of caudate lobe hepatic hemangiomas and to provide an initial description of technical points of the different strategies, to offer evidence-based and actionable references for clinical decision-making regarding this specific anatomical location.

MATERIALS AND METHODS

Patient cohort

From April 2017 to January 2025, 16 patients with hepatic caudate lobe hemangiomas underwent thermal ablation at our single center. All consecutive eligible patients were included during the study period. Due to the clinical characteristics of the disease, the sample size was relatively small but representative. The study was approved by the Ethics Committee of Beijing Chaoyang Hospital (No. 2026-ke-44), and conducted in accordance with the 1975 Helsinki Declaration. Written informed consent was obtained from all participants.

Inclusion criteria: (1) Definite diagnosis of hepatic hemangioma, with a maximum diameter larger than 5 cm; (2) Patients displaying possible hemangioma-related symptoms or progressive enlargement of the hemangioma (> 1 cm over ≥ 2 years); and (3) Patients who declined surgical resection.

Exclusion criteria: (1) Presence of multiple (≥ 2) hepatic hemangiomas; (2) Significant organ dysfunction (e.g., heart, liver, lung, kidney); (3) Active infection, or concomitant malignancy; (4) Previous acceptance of other treatments for hepatic hemangiomas; and (5) Incomplete clinical or follow-up data.

Ablation system

Two types of ablation systems were used in this study. Internally cooled cluster electrodes (Cool-tip ACTC2025 or ACTC1525; COVIDIEN, United States) and a radiofrequency generator (Covidien Healthcare, Ireland) were used for the RFA procedure. With a 2.5 cm exposed tip, the Cooltip electrodes can produce ablation zones of 4.5 cm with the placement of a single applicator and a maximum power of 200 W. For MWA, a microwave therapeutic system (ECO-100A1, ECO Medical Instrument Co. Ltd., Nanjing, China) was used. This system consisted of a microwave generator with a frequency of 2450 MHz, a power output of 0-150 W, and an internally cooled microwave antenna with a 2.0 cm active tip and a 20 cm shaft length.

Ablation procedure

All procedures were performed by hepatobiliary surgeons having more than 10 years of experience in hepatic tumor ablation. Hepatic hemangiomas can be divided into caudate process lesions, paracaval portion, and Spiegel lobe lesions[10]. Depending on the subdivisions of the tumor in the caudate lobe, different treatment protocols were performed. For tumors located in the caudate process, which are situated within the liver parenchyma, CT-guided percutaneous RFA (CT-RFA) was performed. Laparoscopical MWA (LMWA) was the preferred approach for tumors located in the Spiegel lobe, while laparoscopic intratumoral resection (LIRC) facilitated by coagulation was performed for those with significant mass effect[11,12]. For tumors located in the paracaval portion, if the main tumor extends into the Spiegel lobe, LMWA was used. If the tumor protrudes toward the caudate process, CT-RFA was used.

Laparoscopic access to the caudate lobe was achieved by elevating the left lobe of the liver. Thermal ablations were carried out with the percutaneous introduction of a microwave antenna. In some cases, the porta hepatis was encircled with a latex urinary catheter and retracted away from the ablation site. The ablation was performed in automatic mode, and each ablation time was 8-12 minutes. Ultrasound was used for immediate evaluation during the ablation process. Multiple overlapping ablations were performed to obtain a sufficient ablation area when necessary. The ablation process ended when the hyperechoic region produced by thermal ablation was sufficiently large to cover the entire tumor on ultrasound.

For LIRC, the resection margin was marked by diathermy on the surface of the hemangioma about 1.0 cm away from the boundary between the normal liver parenchyma and the tumor. MWA-induced coagulation was performed along the resection margin by laparoscopically introducing ablation electrodes under direct visualization and real-time ultrasound imaging. The detailed operative procedure has been described in our previous work[11].

For CT-RFA, a right intercostal approach was used to insert the radiofrequency electrode needle. This right-sided approach traversed the right hepatic lobe while avoiding the Glisson's sheath and right hepatic vein. CT was utilized for real-time intraprocedural evaluation during ablation. To protect adjacent critical ducts, the ablation margin was not extended beyond the tumor boundary. The ablation procedure was terminated once the ablation region was sufficient to cover the entire tumor.

Post-treatment observation

After ablation, patients were monitored in the hospital to look for any discomfort and ablation-related complications. Ablation-related complications were classified based on the Society of Interventional Radiology (SIR) Adverse Event Classification System[13]. Urine color and volume were closely monitored. Blood count, coagulation tests, and hepatorenal function tests, as well as urine analysis, were performed postoperatively. Patients were discharged from the hospital once they had recovered without any complications.

Treatment outcome and follow-up

One, 6, and 12 months after ablation, enhanced CT or magnetic resonance imaging, measurements of liver function, and symptom assessment were performed to assess the therapeutic effectiveness of ablation and to check for delayed complications. For each lesion, the maximal diameter was recorded at follow-up. The diameter reduction ratio (DRR) was formulated as follows: DRR = (initial volume - final volume)/ initial volume.

Study outcomes

The primary outcomes of the study included technique success, clinical response rate, radiological response rate, and ablation-related complications. The secondary outcomes included procedure time, intraoperative blood loss, complete ablation rate, postoperative hospital stay, and hospital cost. Technique success is defined as the completion of the planned ablation protocol. Radiologic response is defined as a lesion DRR greater than 50% at 12 months. Clinical response is defined as complete or partial relief of hemangioma-related symptoms. Complete ablation was defined as the absence of nodular or irregular enhancement adjacent to the ablation zone.

Statistical analysis

Normally distributed continuous variables are presented as mean ± SD, non-normally distributed variables as median [interquartile range (IQR)], and categorical variables as n (%). Statistical analyses were performed using R Studio 4.2, with P < 0.05 considered statistically significant.

RESULTS

Baseline characteristics

Baseline patients and tumor characteristics are summarized in Table 1. A total of 16 patients with hemangiomas located in the caudate lobe were included in this study. The median age of the study cohort was 35 years (IQR: 32-54). Seven patients (44%) were male, while 9 patients (56%) were female. The median tumor diameter was 7.0 cm (IQR: 6.6-9.7). According to the anatomical subdivision of the caudate lobe, 6 hemangiomas were located in the Spiegel lobe, 3 in the caudate process, and 7 in the paracaval portion.

Table 1 Perioperative data of patients and hemangiomas.

Patient ID	Age/sex	Tumor size (cm)	Location	Reasons for therapy	Treatment method	Operative time (minute)	Intraoperative blood loss (mL)	Postoperative hospital stay (days)	Radiological response	Clinical response	Hospital cost (RMB)
1	33/F	6.4	Paracaval portion	Enlargement of hemangioma	LMWA	130	20	5	Yes	/	29242
2	52/M	10.8	Paracaval portion	Symptom and enlargement of hemangioma	LMWA	150	10	3	Yes	Symptoms present but improved	27018
3	57/F	8.4	Spiegel lobe	Enlargement of hemangioma	LIRC	105	40	1	Yes	/	33427
4	33/F	6.7	Spiegel lobe	Enlargement of hemangioma	LMWA	180	50	4	Yes	/	30562
5	33/F	6.0	Spiegel lobe	Symptom related to hemangioma	LMWA	40	10	2	Yes	Disappearance of symptoms	35548
6	54/F	11.0	Spiegel lobe	Enlargement of hemangioma	LMWA	165	20	6	Yes	/	29003
7	42/M	12.0	Paracaval portion	Symptom and enlargement of hemangioma	LMWA	130	30	2	Yes	Disappearance of symptoms	28794
8	29/M	7.0	Spiegel lobe	Enlargement of hemangioma	LIRC	120	45	3	Yes	/	35980
9	55/M	6.5	Paracaval portion	Symptom and enlargement of hemangioma	CT-RFA	30	0	2	Yes	Disappearance of symptoms	36125
10	66/M	7.0	Caudate process	Symptom and enlargement of hemangioma	CT-RFA	20	0	4	Yes	Disappearance of symptoms	26643
11	29/M	6.7	Paracaval portion	Enlargement of hemangioma	CT-RFA	30	0	2	Yes	/	29650
12	53/M	9.8	Paracaval portion	Enlargement of hemangioma	LMWA	80	10	5	Yes	/	29406
13	36/F	6.7	Caudate process	Enlargement of hemangioma	CT-RFA	30	0	1	Yes	/	27964
14	28/F	7.0	Caudate process	Enlargement of hemangioma	CT-RFA	25	0	1	Yes	/	36329
15	31/F	6.0	Spiegel lobe	Enlargement of hemangioma	LMWA	165	15	2	Yes	/	27076
16	32/F	9.6	Paracaval portion	Enlargement of hemangioma	LMWA	130	10	3	Yes	/	23723

F: Female; M: Male; LMWA: Laparoscopic microwave ablation; LIRC: Laparoscopic intratumoral resection facilitated by coagulation; CT-RFA: Computed tomography-guided radiofrequency ablation.

Among the 16 patients, progressive enlargement was present in 15 (94%): 11 had enlargement alone, and 4 had both enlargement and hemangioma-related symptoms. The median pre-ablation observation period was 54 months (IQR: 36-78), during which the median increase in maximum tumor diameter was 4.0 cm (IQR: 2.0-4.8).

Intraoperative results

Regarding the treatment modalities, for the 6 hemangiomas in the Spiegel lobe, all underwent LMWA (Figure 1), among which 2 cases received LIRC (Figure 2). For the 3 patients with tumors in the caudate process, all were treated with CT-RFA (Figure 3). Among the 7 patients with tumors in the paracaval portion, 5 underwent LMWA, and the remaining 2 received CT-RFA. The technical success rate was 100%. The mean ablation time was 113min (IQR: 30-135). The median intraoperative blood loss was 10 mL (IQR: 0-23). No patient received blood transfusions during or after the operation. In terms of lesions that underwent thermal ablation only, the complete ablation rate was 86% (12/14).

Figure 1 Microwave ablation of a 6.4 cm hepatic Spiegel lobe hemangioma. A-C: Preoperative computed tomography (CT) scan demonstrated a 6.4 cm hepatic caudate lobe hemangioma (Spiegel lobe); D-F: Expose the hepatic hemangioma and perform microwave ablation; G-I: Follow-up abdominal contrast-enhanced CT at 3 months postoperatively.

Figure 2 Laparoscopic intratumoral resection facilitated by coagulation of a 7.0 cm hepatic Spiegel lobe hemangioma. A: Contrast-enhanced computed tomography (CT) demonstrated a 7.0 cm hepatic hemangioma in the Spiegel lobe; B: Expose the hemangioma in the hepatic Spiegel lobe; C and D: The resection margin was on the hemangioma about 1.0 cm away from the boundary between the normal liver parenchyma and the tumor. Ablation-induced coagulation was performed along the resection margin by percutaneously introducing a microwave antenna under direct visualization; E and F: The hepatic hemangioma was dissected along the coagulation-marked resection margin using a harmonic scalpel; G: The hemangioma was removed, and a 1.0-cm band of ablation-coagulated hemangioma was left in place; H: The ablation antenna was used to achieve hemostasis on the resection surface of the hepatic hemangioma; I: Contrast-enhanced CT shows that the hemangioma was completely resected without residual tissue.

Figure 3 Percutaneous computed tomography-guided radiofrequency ablation of a 6.5 cm hepatic paracaval portion hemangioma. A: Preoperative computed tomography (CT) scan demonstrated a hepatic caudate lobe hemangioma of 6.5 cm in paracaval portion of the caudate lobe; B: CT image showing radiofrequency needle within the lesion, lesion approached through the right intercostal approach; C: Follow-up CT at 1 month showed that the hemangioma was significantly smaller than before and had no enhancement.

Postoperative results

Totally, 16 procedures of thermal ablation were performed; the radiologic response rate was 100%. Among the 5 patients who had hemangioma-related symptoms, 4 had a complete clinical response, and 1 had a partial clinical response. Clinical response rate was 100%. Two patients (13%) developed postoperative fever, and one (6%) experienced hemoglobinuria; all events resolved spontaneously within 72 hours (SIR class A). The median postoperative hospital stay was 3 days (IQR: 2-4). The median hospitalization cost was RMB 29324 (IQR: 27520-34487).

The median follow-up duration was 21 months (IQR: 15-33). During the follow-up period, changes in mean maximal diameter and DRR of the therapy area after thermal ablation were shown in Figure 4 and Table 2. In the follow-up CT scans, the average maximum diameter decreased significantly (all P < 0.05). No tumor recurrence was observed in any patient. In cases of incomplete ablation, no progression of residual tumor was detected during follow-up.

Figure 4 Line chart showing changes in hepatic caudate lobe hemangioma diameter.

Table 2 Changes in the maximal diameter of the lesions after treatment at each follow-up, mean ± SD/median (interquartile range).

	Diameter	DRR	P value
Baseline	7.0 (6.7-9.6)
1 month	5.0 ± 2.6	2.3 (2.0-2.8)	< 0.001
6 months	3.6 ± 2.1	3.9 (3.6-4.8)	< 0.001
12 months	1.0 (0.0-1.8)	6.8 ± 1.1	< 0.001

DRR: Diameter reduction ratio.

DISCUSSION

The present study demonstrates that thermal ablation with an integrated plan is an effective and safe alternative treatment for patients with hepatic hemangioma in the caudate lobe. The rates of technical success and radiologic response were both 100%. Among the 5 patients with preoperative symptoms, the clinical response rate was 100.00%. No major complication was observed.

Theoretically, the benign nature of hepatic hemangiomas implies that no lesion is absolutely unresectable. However, due to the unique anatomical location of the caudate lobe, the caudate lobectomy accounts for only 0.5% to 4% of hepatic resection[14]. Surgical resection of hemangiomas in challenging locations, notably the caudate lobe, is associated with significantly increased technical difficulty and perioperative risk[15]. The caudate lobe is deep and hard to expose, with the first hepatic portal at the lower front, the second hepatic portal at the upper side, and the inferior vena cava (IVC) and third hepatic portal at the back. At the same time, it is connected with various hepatic portal structures by abundant vessels. Giant hemangiomas in the caudate lobe can completely occupy the upper abdomen and leave little room for surgical operations. Moreover, because the incidence of caudate hemangioma is lower than that of the left or right hepatic hemangioma, and the potential technical challenge, the reports about caudate lobectomy mainly derived from a limited number of case-series with small sample sizes, do not provide a robust basis for definite conclusions[14,16]. Thus, the application of surgical resection for caudate hemangioma requires careful consideration.

When surgical resection is not optimal, alternative treatment should be considered. Transcatheter arterial embolization has been used as a minimally invasive treatment option[17]; however, its efficacy is highly dependent on tumor vascularity[18,19], and long-term outcomes remain unsatisfactory.

Thermal ablation has emerged as a minimally invasive and effective treatment for symptomatic hepatic hemangioma[1,5]. Xu et al[1] retrospectively analyzed 357 patients with 378 hepatic hemangiomas treated with CT-guided or laparoscopic thermal ablation and showed that ablation was successful in all patients; 95.5% of the hemangiomas were completely ablated. Cai et al[9] reported that after ultrasound-guided MWA of 56 lesions in 54 cases, the technique efficacy rate was 100%. However, to date, thermal ablation for caudate lobe hemangiomas has been limited to a single case report[7]. No cohort study has systematically evaluated the safety and efficacy of thermal ablation specifically for hepatic caudate lobe hemangiomas. The present study represents the first case series to address this clinical gap.

In our study, we retrospectively analyzed the safety and efficacy of 16 patients with 16 hepatic hemangiomas in the caudate lobe treated by thermal ablation. Regarding the safety of thermal ablation, key perioperative outcomes demonstrated improvement. According to a systematic review of laparoscopic caudate lobe resection, the mean operative time, volume of intraoperative blood loss, and length of hospital stay were 225 minutes, 134 mL, and 7 days, respectively[16]. In our cohort, the median operative time was 113 min (IQR: 30-135), the median blood loss was 10 mL (IQR: 0-23), and the median postoperative stay was 3 days (IQR: 2-4). Each of these measures represents a meaningful reduction compared to established benchmarks in prior studies. Although instances of mortality and various complications following surgical resection have been documented in prior studies[16]. No major ablation-related complications or deaths occurred in our series. Thus, the safety of this procedure is satisfactory. This is closely related to the accumulation of our years of experience, as well as the integrated ablation strategies.

The application of thermal ablation in the caudate lobe theoretically faces two sets of challenges: One is the anatomical and technical challenges, and the other is ablation-related hemolysis. To address the anatomical and technical challenges, the implementation of an individualized treatment strategy was carried out. Laparoscopic ablation was applied for hepatic hemangiomas in the Spiegel lobe. The laparoscopic approach to the Spiegel lobe lesion is from the left side, established by elevating the left lobe of the liver. Laparoscopic instruments were used to isolate the gastrointestinal tract, and a tape was applied to simultaneously suspend and protect the first porta hepatis, thereby providing adequate exposure of the operative field. Under laparoscopic guidance, microwave antennas are percutaneously inserted into the lesion. The electrode trajectory is kept as parallel as possible to major blood vessels, maintaining a distance of at least 1 cm. And the MWA is performed progressively from near to far and from the bottom upward. This allows for direct laparoscopic observation of tumor shrinkage and collapse, thereby creating operational space for subsequent ablation. Additionally, hepatic hemangiomas located in the caudate process were treated by CT-RFA. The selection of RFA was primarily based on two considerations. Firstly, the microwave antenna is relatively thick (14 G vs 17 G for RFA electrodes), which increases the risk of puncture-related bleeding when traversing the narrow anatomical corridor of the caudate process. Secondly, MWA offers rapid heating and high thermal efficiency, which is advantageous for large-volume ablation but poses challenges in anatomically constrained spaces. The caudate process is wedged between the IVC posteriorly and the right portal bifurcation anterosuperiorly. The more gradual and predictable thermal diffusion of RFA facilitated control of the ablation zone margin and reduced the risk of thermal injury to these critical vascular structures. Furthermore, particular attention was paid to tumors involving the paracaval portion of the caudate lobe, given its critical location anterior to the IVC and immediately posterior to the roots of the major hepatic veins. If the tumor extended into the Spiegel lobe, the approach mirrored the strategy for Spiegel lobe lesions, prioritizing safe access and mobilization. Conversely, if the tumor protrudes along the IVC toward the interior of the liver or the caudate process, the techniques and considerations for managing caudate process lesions were applied.

Hemolysis after thermal ablation is inherently determined by the histological structure of the hemangioma, as tumor size increases and ablation time lengthens, the risk of ablation-induced hemolysis and its related complications rises[6,20]. Several studies have shown that MWA offers distinct advantages over RFA, including shorter ablation time and fewer hemolysis-related complications. In our cohort, MWA was only avoided in 5 caudate process lesions for safety considerations. If the tumor exhibits a significant mass effect, LIRC is performed. Compared with treatment using ablation alone, intratumoral resection facilitated by coagulation involved the ablation of the tumor tissue at the resection margin rather than the total hemangioma, and thus, shortened the ablation time and avoided severe ablation-related complication[11]. Additionally, perioperative fluid management can be implemented to avoid hemolysis-related organ damage.

In our cohort, the efficacy of thermal ablation for hemangiomas in the caudate lobe was favorable. The rate of radiologic response was 100%; all 5 patients with hemangioma-related symptoms experienced symptom relief. Moreover, previous literature reports a conversion rate to open surgery of 3% for laparoscopic surgical resection, whereas in our study, all ablation procedures achieved technical success[16].

Several groups have described thermal ablation of caudate malignant tumors[21]. Due to the sufficient ablative margin, local tumor progression is higher in caudate lesions than in other liver segments[21,22]. In our study, the complete ablation rate was 86%. However, unlike the “complete and thorough ablation” principle applied to malignant hepatic tumors, the therapeutic goal for benign tumors should focus on enhancing disease control and preserving patients’ quality of life. It is unnecessary to sacrifice treatment safety in pursuit of the “safe ablation margin” a key requirement for malignant tumor ablation-particularly for hepatic hemangiomas located in the hepatic caudate lobe. In all those incompletely ablated lesions, significant reductions in tumor volume were observed. Moreover, within the follow-up period, no progression occurred in the residual tumor.

To the best of our knowledge, our study represents the first exploration of the potential of thermal ablation as an alternative treatment for hepatic caudate lobe hemangiomas and provides corresponding technical considerations and recommendations for perioperative management.

This study has three main limitations. First, this is a retrospective study rather than a randomized controlled trial. Second, the single-arm design precludes direct comparison with alternative minimally invasive treatment modalities. Third, the sample size was relatively small, particularly due to the rarity of caudate lobe cases. Despite these limitations, this case series establishes the feasibility of thermal ablation for caudate tumors. Further multi-center, prospective, randomized controlled studies are needed.

CONCLUSION

In conclusion, thermal ablation for hepatic caudate lobe hemangiomas is a safe, feasible, and effective minimally invasive therapeutic modality.