Laparoscopic-Assisted Microwave Ablation for Splenic Hemangioma: A Case Report and Literature Review

Introduction

Splenic hemangioma is an uncommon lesion that occurs more often in women, with an estimated incidence of 0.02–0.16% [1,2]. Splenic hemangioma is still regarded as the most frequent benign tumor of the spleen. Most patients remain asymptomatic [3], but some have abdominal discomfort, diarrhea, or even respiratory problems [3]. Because of the unique structure of splenic tissue [4,5], percutaneous biopsy – while theoretically the diagnostic gold standard – is rarely undertaken in practice [6–10]. Instead, diagnosis is usually based on characteristic imaging findings, supplemented by laboratory tests when necessary. To date, there are no clinical practice guidelines or expert consensus statements that clearly define indications for treatment. Some investigators recommend intervention for lesions ≥4 cm [3,11,12], whereas others suggest using 5 cm as the cutoff [2,13].

Reported treatment options for splenic hemangioma include open splenectomy (OS), laparoscopic total splenectomy (LTS), laparoscopic partial splenectomy (LPS), and robot-assisted partial splenectomy (RAPS). LTS is commonly performed because it is minimally invasive [2,14,15]. However, since the spleen is critical to both innate and adaptive immunity [16–19], removing it completely greatly increases the risk of overwhelming post-splenectomy infection (OPSI), with mortality rates ranging from 50% to 80% [20–24]. In contrast, LPS and RAPS preserve splenic function but are technically demanding and often have longer operative times, greater blood loss, and higher costs [2,11,25]. At present, there is still no ideal approach that balances safety, minimal invasiveness, and preservation of spleen function.

Thermal ablation has gained increasing use in recent years for treatment of hepatic hemangioma (HH) [26–32], and is valued for its minimally invasive nature and rapid hemostatic effect. However, in giant hepatic hemangioma (GHH), reports of severe postoperative hemolysis and acute kidney injury (AKI) have become more frequent, which has limited its wider adoption [33]. The spleen, with its rich vascularity and essential roles in immunity and blood storage, is at even higher risk when ablation is attempted. Few publications have described the use of microwave ablation (MWA) to control bleeding at the residual splenic margin after laparoscopic partial splenectomy (LPS) [11,34], and no study has directly reported laparoscopic microwave ablation (LMWA) as a treatment for splenic hemangioma. Building on more than 2 decades of experience in tumor ablation and related research, our team developed a novel approach that combines LMWA with controlled phlebotomy. By creating small “gas-blood outflow channels” on the surface of the lesion, this technique reduces the amount of free hemoglobin (Hb) entering the circulation and markedly improves procedural safety. To the best of our knowledge, this is the first case report to describe LMWA for splenic hemangioma in detail, highlighting its feasibility, safety, and potential as a cost-effective, spleen-preserving treatment option.

Case Report

A 67-year-old woman was hospitalized for evaluation of a 2-year history of progressively enlarging splenic hemangioma. She was found to have a splenic hemangioma during a routine check-up in 2023, when the lesion measuring 3.7×3.8 cm. She had no symptoms at the time, such as abdominal pain or diarrhea. Follow-up imaging in 2024 showed that the lesion had grown to 5.2×4.3 cm, yet she remained symptom-free. Shortly before admission, an ultrasound revealed further enlargement, with the lesion reaching approximately 6.0 cm in diameter. She had no history of infectious diseases, such as hepatitis or malaria, no chronic conditions, no abdominal trauma, and no history of living abroad. She had no family history of splenic tumors. Results of the physical exam were normal.

The abdomen was soft and non-tender, with no rebound tenderness. Blood tests showed a D-dimer level of 572 ng/mL. Tumor markers – AFP, CA125, CA15-3, and CA72-4 – were all normal. The rest of the lab results were unremarkable. After admission, contrast-enhanced abdominal CT showed a large mass at the upper pole of the spleen with a distinctive ring of enhancement during the arterial phase (Figure 1A). The lesion became slightly denser in the venous phase and measured about 6.0×5.6 cm (Figure 1B). Before surgery, 3D reconstruction of the splenic hemangioma was performed, clearly revealing the origin of its feeding artery (Figure 1C). Enhanced CT showed a lesion with relatively slow enhancement and clear margins, and the patient had no symptoms, supporting a likely diagnosis of splenic hemangioma splenic hemangioma. Splenic lymphangiomas usually appear as multilocular cystic lesions, which were not seen in this case, making this diagnosis unlikely. Vascular malignancies of the spleen, such as angiosarcoma, tend to present as poorly defined masses with systemic symptoms like fever or weight loss; none of these were present, further lowering their likelihood. At admission, chest X-ray and preoperative tests, including tumor markers, were all normal, effectively ruling out metastatic disease. Postoperative paraffin pathology confirmed that the lesion was consistent with a splenic cavernous hemangioma, which was in accordance with the clinical diagnosis (Figure 2).

We used a 2450 MHz microwave system (KY-2000 dual-source floor-standing; Kangyou Medical, China) for the procedure. This system includes 2 independent microwave generators, 2 flexible coaxial cables, and 2 water pumps, allowing simultaneous use of two 18-cm disposable microwave ablation needles with 1.5-cm antenna tips and cooling shafts. Each generator can deliver power between 1 and 100 W. An experienced hepatobiliary surgeon performed the procedure according to the preoperative plan. An MWA equipment operator monitored urine color changes in real time during the operation and manually controlled the ablation time as needed.

After anesthesia was successfully induced, the patient was placed in a supine position with the right arm abducted, head elevated, feet lowered, and upper body tilted to the left. Percutaneous ultrasonography revealed a hemangioma at the upper pole of the spleen, measuring approximately 6 cm in diameter. A 1-cm incision was made just below the umbilicus, through which a Veress needle was inserted to establish pneumoperitoneum. Once adequate insufflation was achieved, a 10-mm trocar was introduced, followed by the insertion of a 30° laparoscope into the abdominal cavity. Dense adhesions were found between the upper pole of the spleen and the lateral wall of the stomach. A localized exophytic splenic hemangioma was identified. A 5-mm trocar was placed just below the left costal margin, slightly inferior to the xiphoid midline, and a 12-mm trocar was positioned symmetrically on the right side (Figure 3).

A disposable suction device was inserted, and the left lateral lobe of the liver was lifted. The ligaments connecting the stomach and spleen were carefully separated to expose the upper pole of the spleen. A 6-cm exophytic splenic hemangioma was seen, surrounded by abundant blood vessels. Under direct laparoscopic visualization, a needle biopsy of the splenic hemangioma was performed as part of the LMWA procedure. The tissue specimen was promptly processed for routine paraffin-embedded histopathological examination. Using laparoscopic guidance and intraoperative ultrasound, 2 disposable ablation electrodes (KY-450B-T7) were placed at the bases of the splenic hemangioma’s upper and lower poles and were secured to prevent movement (Figure 4A). Gentle pressure was applied to the splenic hemangioma surface with the suction device to temporarily reduce blood flow in the communicating vessels. Electrode positions were checked again with ultrasound, and the power was gradually increased to perform the ablation step by step (Figure 4B).

After the first ablation, the electrode was repositioned for a second ablation to ensure complete treatment of the splenic hemangioma. Ultrasound was used throughout to monitor the heat-irrigate effect (HIE) in the lesion and surrounding spleen, as well as to observe changes in spleen color. Gentle pressure was applied to the spleen surface with a disposable suction device to aspirate blood containing damaged red blood cells leaking from the puncture site of the initial ablation (Figure 4C). Once ablation was complete, the electrode was removed, and bleeding at the puncture site was controlled. The area was thoroughly flushed with normal saline, bleeding was checked again, laparoscopic instruments were withdrawn, and the incision was closed with absorbable subcutaneous sutures (YA-2021Q). The entire procedure lasted 80 minutes, including 25 minutes of ablation, with an estimated blood loss of 20 mL.

During surgery and on the first day after, 125 mL of 5% NaHCO3 solution was given to alkalize the urine, along with adequate fluids and diuretics (furosemide). Blood counts, liver and kidney function, urine tests, coagulation (Figure 5A), IL-6, and PCT were checked on days 1, 2, and 3 after surgery. Although inflammatory markers (IL-6, PCT) went up right after surgery, they dropped significantly as the patient steadily recovered (Figure 5B, 5C). AST levels rose briefly after the operation but returned to normal by day 3, platelet levels fell briefly but also returned to normal by day 3, and postoperative renal function levels remained essentially normal (Figure 5D–5F).

We used the Clavien-Dindo classification to categorize complications related to splenic hemangioma treatment [35]. These typically include pleural effusion, pancreatic fistula, wound and lung infections, splenic abscess, postoperative bleeding, and acute kidney injury. The patient developed hemoglobinuria (HbU) 24 hours after surgery, but urine occult blood tests were negative by 48 hours. No serious complications occurred after LMWA.

Before discharge, an enhanced abdominal CT scan showed an ablation area about 5.7×5.5 cm in size, with no enhancement ring visible around the edge of the splenic hemangioma lesion during the arterial phase (Figure 6A, 6B). The patient was discharged on the fifth day after surgery.

At 6 months after the procedure, she remained symptom-free and had no complications related to thermal ablation. Follow-up contrast-enhanced magnetic resonance imaging (MRI) of the upper abdomen showed no new splenic hemangioma lesions, and the ablation area had shrunk to 3.83×3.52 cm (Figure 6C, 6D).

Discussion

Splenic hemangioma is the most common benign splenic tumor [36,37]. Most patients are asymptomatic [38,39], but some have abdominal discomfort. Spontaneous rupture is rare (1 of 31 reported cases [3.2%]) [1,40]. Larger splenic hemangioma can cause compression, affect coagulation, and, in severe cases, lead to Kasabach-Merritt syndrome.

There are currently no established guidelines for managing splenic hemangioma [2]. Some experts suggest considering surgery for lesions 4 cm or larger [41], while others use 5 cm as the threshold [2,13]. Treatment options include medication, transarterial embolization (TAE), surgical resection, and thermal ablation [42]. OS has traditionally been the mainstay, but LTS has gradually become the preferred approach [44,45] since was first reported in 1992 [43]. However, total splenectomy is often difficult to justify for benign disease because the spleen plays a crucial role in immunity [22,46,47]. Studies show that preserving as little as 25% of splenic tissue is enough to maintain normal immune function [2,16,48,49], which has led to growing interest in spleen-preserving procedures such as LPS and RAPS, but spleen-preserving surgery still has challenges. First, if the splenic hemangioma is supplied by multiple splenic arteries, the procedure can be technically demanding, especially laparoscopically, and the risk of intraoperative rupture and bleeding increases. Second, patients with Kasabach-Merritt syndrome often have coagulopathy, making hemostasis on the remaining spleen more difficult and raising the risk of hemorrhagic shock. Third, for larger splenic hemangiomas, spleen-preserving surgery does not always offer clear advantages over total splenectomy and can result in longer operation times, more postoperative pain, and extended hospitalization [44,50].

Thermal ablation has been used with some success on the residual splenic surface for hemostasis [11,34], but there are still no case reports of it being used as a definitive treatment for splenic hemangioma. The main challenge is the spleen’s rich blood supply and large blood volume. Studies show that heating red blood cells to 60°C for 5 minutes causes significant hemolysis, releasing large amounts of cell-free Hb [51], which can result in hemoglobinuria (HbU) and, in severe cases, AKI. Controlling this postoperative hemolytic response remains a major barrier to using thermal ablation in splenic hemangioma. Furthermore, evidence suggests that radiofrequency ablation (RFA) carries a higher risk of hemolysis than MWA, making MWA a more promising option [29,52].

Building on our experience with HH, we have developed an innovative approach using LMWA combined with a “blood release” technique for treating splenic hemangioma. Unlike percutaneous ultrasound-guided microwave ablation (UMWA), LMWA allows direct, real-time visualization of the ablation zone, avoids ultrasound artifacts, and prevents delayed needle tract bleeding. We also create a small “gas-blood outflow channel” on the splenic hemangioma surface, which enables damaged blood cells to drain into the abdominal cavity during ablation, reducing the release of cell-free Hb into the circulation and lessening the hemolytic response. Importantly, the splenic feeding arteries are first ablated to reduce tumor blood flow, which shortens ablation time and improves procedural safety.

The coagulated area seen after ablation does not indicate residual or recurrent disease, but is composed of inactivated splenic hemangioma tissue. This thermal effect differs from simple coagulative necrosis; over time, the ablated tissue gradually shrinks and eventually stabilizes once it reaches a certain size [53].

This report has several limitations. First, as a case report and literature review, its small sample size calls for further validation through multi-center, large-scale clinical trials. Second, the safety of LMWA relies heavily on the surgeon’s understanding of key principles such as HIE [54], heat-sink effect (HSE), heat-conductive effect (HCE), and oven effect (OE). Junior surgeons, in particular, need to build a solid foundation in these techniques to ensure safe and effective application.

Conclusions

This is the first report of the feasibility and safety of LMWA for treating splenic hemangioma. This approach effectively reduces intraoperative bleeding and postoperative hemolysis while preserving splenic function, offering a novel treatment option for splenic hemangioma.