The most common type of mesenchymal tumor in the digestive tract is the gastrointestinal stromal tumor (GIST). Metastases occur in around 15–47% of GIST, with the liver and peritoneum being the primary locations. Metastases to the lung, bone, and soft tissue are extremely uncommon and typically observed in patients with advanced disease (3). Surgical resection is not appropriate for advanced GIST with multiple metastases. Approximately 10–15% of GIST exhibit specific gene mutations and exhibit resistance to targeted therapy (4). Radiotherapy provides analgesic effects for bone metastases, with a relief rate of 60% (5). Nevertheless, GIST is classified as a mesenchymal tumor and is known to have a limited response to chemotherapy and radiotherapy (6). Thermal ablation is an effective treatment for reducing the pain caused by bone metastases from cancer (7). However, there are currently no cases or studies on the efficacy of ablation for treating bone metastases, specifically GIST.

In January 2022, a 58-year-old man was admitted to Sichuan Cancer Hospital with left-sided back pain that radiated to the chest. In 2014, he was diagnosed with gastric GIST and underwent a complete surgical excision followed by targeted therapy. In 2018, he developed sacral metastases and underwent a vertebrotomy. In 2019, he experienced rib metastasis and received treatment with radiotherapy, targeted therapy, and immunotherapy. But his chest wall pain persisted, scoring a 5 out of 10 on the numerical rating scale (NRS). The timeline of the clinical events was shown in Figure 1 .

GIST is the prevailing mesenchyme tumor of the digestive tract. 30% of GIST patients develop metastasis after radical resection of primary tumors (10). Metastases to soft tissue and bone are uncommon and typically appear in advanced GIST. Pain relief and functional improvement are the principal objectives of bone metastases. The conventional approach for managing GIST metastasis is targeted therapy. However, primary resistance is present in 10–15% of patients, and secondary resistance develops in approximately 40–50% of patients (11). A variety of factors, including the patient’s physical condition and the number, location, and size of metastases, may impede the application of surgery. Radiotherapy provides pain alleviation for approximately 60% of patients, but it is not commonly used for GIST due to their general resistance to normal radiation doses applied to sarcomas (12). Furthermore, radiotherapy results in adverse effects such as radiation pneumonia, cardiac damage, and second malignancy, the occurrence of which is positively connected with radiation dose (13). Recent research suggest that immune checkpoints and gene mutations are associated with clinical behavior of GIST, but there is a lack of adequate clinical studies to support it (14).

MWA is a minimally invasive therapy, and studies have demonstrated its safety and efficacy in treating painful bone metastasis (15). Nevertheless, there were no case reports or studies using MWA to treat GIST bone and soft tissue metastases. We reported the case of a patient who developed metastases following surgical resection of the primary tumor and targeted therapy. Despite receiving multidisciplinary treatments, he was still experiencing unbearable pain in his chest wall and required immediate pain relief.

Coagulation necrosis and an inflammatory reaction were brought on by ablation (9, 16). As the size of the ablated tumor increased, so did the duration of ablation; additionally, complications became more likely (17). Multiple ablations may be employed for large or recurrent tumors (18). Because the tumor in this instance was big and close to the spleen, we chose to ablate a portion of it initially and then undergo another ablation after the tumor shrank. The size of the lesion had decreased to 5.3×2.4 cm three months subsequent to the initial ablation. The patient, who was in good condition, requested a second ablation. Throughout the two procedures, a liquid barrier was created, and a high-power, short-duration ablation strategy was employed to minimize thermal damage. In addition, real-time ultrasound guidance was used during the treatments to minimize harm to crucial structures. There were no adverse effects from the ablation procedure. He maintained a 17-month follow-up until September 2023. The pain in the chest wall significantly improved (2 vs. 5). The size of the lesion was decreased to 4.7×1.6 cm from its preoperative size of 5.6×3.2 cm.

To our knowledge, this is the first report of the utilization of MWA for the treatment of bone and soft tissue metastases in GIST. Ablation has the potential to offer pain alleviation with little occurrence of complications and a high level of repeatability. When the tumor is large, repeated ablations may be necessary to prevent complications. Nevertheless, given this is a case report, more research is required to confirm the effectiveness of MWA on bone metastases from GIST.

The original contributions presented in the study are included in the article/supplementary material. Further inquiries can be directed to the corresponding author.

The study was approved by the Medical Ethics Committee of the Sichuan Cancer Hospital and Institute (SCCHEC-02-2016-001). Written informed consent was obtained from the individual for the publication of any potentially identifiable images or data included in this article.

All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication. SW, MZ, ML designed the study and drafted the manuscript. LW, TL, and YL collected and analyzed the literature. SW wrote the manuscript, and ML supervised the study and critically revised the manuscript. All authors contributed to the article and approved the submitted version.