Post-radiofrequency ablation empyema—a staged multidisciplinary protocol for colonic and diaphragmatic perforation: a case report

Introduction

Percutaneous radiofrequency ablation (RFA) is an effective local therapy for unresectable small hepatic tumors. Its widespread global adoption is attributable to its minimal invasiveness and favorable local control rates. Although RFA has a high safety profile, it is not devoid of complication risks. Overall complication rates are reported at 8.9% (1), with major complication rates ranging from 4.1% to 5.6% (2,3). Common complications include hemorrhage, liver abscess, and biliary injury. By contrast, gastrointestinal perforation and diaphragmatic injury are exceedingly rare, with reported incidences of 0.5% (4) and 0.1% (1), respectively. Such events can precipitate a cascade of life-threatening sequelae, including peritonitis, subphrenic abscess, and empyema, particularly when a direct communication forms between the abdominal and thoracic cavities. The literature has not established a standard of care for this complex pathology. Here, we detail a case of acute empyema following colorectal and diaphragmatic perforation after RFA, which we managed successfully using a staged, multidisciplinary approach focused on source control. We present this article in accordance with the CARE reporting checklist (available at https://acr.amegroups.com/article/view/10.21037/acr-2025-327/rc).

Case presentation

A 76-year-old man previously treated for descending colon cancer and multiple liver metastases, who had undergone partial colectomy, chemotherapy, and several hepatectomies, presented to Keiyukai Sapporo Hospital with fever and malaise. He subsequently received three sessions of RFA at another facility for recurrent hepatic disease, the last of which targeted two lesions in segment 4. He also had underlying Child-Pugh B liver cirrhosis. The patient’s symptoms developed 90 days following his third RFA, necessitating his referral. On admission, despite the severe infection, his Eastern Cooperative Oncology Group (ECOG) performance status was 0. Laboratory results revealed leukocytosis (12,700/µL), markedly elevated C-reactive protein (27.32 mg/dL), and hypoalbuminemia (2.1 g/dL). A contrast-enhanced computed tomography (CT) scan of the chest and abdomen demonstrated an 8-cm gas-containing abscess in the right subphrenic space (Figure 1A,1B). This abscess was contiguous with multiple suspected diaphragmatic fistulae and an encapsulated right-sided pleural effusion. Crucially, the imaging strongly suggested a communication between the subphrenic abscess and the transverse colon. Based on these findings, we made a preoperative diagnosis of acute empyema resulting from post-RFA colonic and diaphragmatic perforation. We then implemented a staged therapeutic strategy based on the principle of source control (5-8).

• Stage 1: thoracic infection control. On day 1, we initiated right-sided chest drainage, which yielded a large volume of turbid, feculent fluid, confirming a gastrointestinal communication. Cultures grew E. coli, and we began systemic antibiotics. On day 8, we performed thoracoscopic debridement, identifying three diaphragmatic fistulae with effluent of enteric-like contents. Because severe intra-abdominal adhesions precluded primary repair, we performed only debridement, irrigation, and drainage (Figure 2A,2B).
• Stage 2: abdominal source and perforation control. By day 11, the chest tube effluent had become overtly fecal, underscoring the need for definitive abdominal source control. After consulting with the general surgery team, we chose not to perform single-stage radical surgery due to extensive adhesions. We first performed a diverting loop ileostomy to mitigate fecal contamination. Twenty-five days later (day 36), the general surgery team performed a right hemicolectomy, including the perforated colonic segment, with stoma closure. During the colectomy, they identified the diaphragmatic fistula. Direct suture closure was not feasible due to severe tissue induration caused by chronic inflammation. Therefore, they performed a patch closure using a flap of Gerota’s fascia mobilized from the right kidney. Concurrently, the thoracic surgery team performed repeat thoracoscopic debridement and decortication.
• Stage 3: management of refractory empyema and air leak. Following colectomy, contamination from the digestive tract ceased; however, the pleural infection persisted with cultures growing methicillin-resistant Staphylococcus aureus (MRSA). The patient also had a persistent air leak that prevented lung re-expansion and caused a residual empyema cavity. To manage this refractory state, we performed an open window thoracostomy on day 63. As the air leak continued despite good wound granulation, we performed bronchoscopic bronchial occlusion with endobronchial Watanabe spigots (EWS) on day 139. Using 3D navigational guidance, we successfully occluded the responsible bronchi, which resolved the air leak (Figure 3A,3B). After the wound became clean, we discontinued antibiotics, and the patient left the hospital on day 162 after rehabilitation. At 15-month follow-up, the patient remains well with no radiological evidence of recurrent empyema (Table 1).

Figure 2 Intraoperative thoracoscopic findings. (A) The thoracic cavity is filled with turbid, feculent-appearing fluid, indicating a direct communication with the gastrointestinal tract. (B) Multiple fistulous openings are visible on the surface of the diaphragm after irrigation.

Figure 3 Bronchoscopic bronchial occlusion using EWS. (A) Bronchoscopic view of the target bronchi (B4^a+b, B4^c, and B5) before occlusion. (B) Post-placement view showing successful bronchial sealing and resolution of the persistent air leak. EWS, endobronchial Watanabe spigots.

Figure 1 Preoperative CT findings. (A) Axial CT shows a subphrenic abscess with gas (arrow) adjacent to the liver. (B) Coronal CT reveals a large, multiloculated right-sided empyema and a suspected diaphragmatic fistula (arrow) connecting the subphrenic abscess to the pleural cavity. CT, computed tomography.

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Discussion

RFA is an important therapeutic option for hepatic tumors but carries a tangible risk of severe complications. Diaphragmatic perforation after RFA is rare, with proposed mechanisms including proximity of the target lesion, thermal injury, and impaired healing due to cirrhosis (5). In this case, the delayed onset of 90 days strongly suggests a progressive pathology. This delay is characteristic of thermal injury, which causes gradual ischemia and necrosis rather than immediate mechanical perforation. Furthermore, the subphrenic abscess was likely contained initially, masking acute symptoms. Although pathological confirmation of the perforation site was not obtained, we hypothesize that RFA caused thermal injury to the adjacent colon, leading to delayed perforation. The resulting subphrenic abscess then likely eroded through the thermally weakened diaphragm, creating a pleuro-colonic communication.

This complex clinical cascade mandates a clear therapeutic strategy. Prompt and definitive source control—encompassing drainage, debridement, and restoration of anatomical integrity—is paramount in treating intra-abdominal sepsis and dictates prognosis (6-9). Our approach aligned with these principles. We employed a staged strategy, first controlling the thoracic sepsis (Stage 1), then collaborating with general surgery to eliminate the abdominal source (Stage 2). Finally, we addressed the residual refractory empyema and air leak with an open window thoracostomy and EWS (Stage 3), which are effective modalities for such complex pleural problems (10). Specifically, we selected open window thoracostomy because lung expansion was not achieved after the initial debridement, and the empyema was refractory to standard drainage. Alternative strategies, such as repeat video-assisted thoracoscopic aurgery (VATS) or the Clagett procedure, were considered less feasible due to the persistent lung non-expansion, ongoing air leak, and severe pleural contamination. Regarding the air leak, surgical closure of the bronchopleural fistula was deemed unsafe due to severe adhesions. EWS was chosen over other valves because the target bronchi were peripheral (B4 and B5), making them suitable candidates for this specific occlusion technique. This case critically underscores the value of a staged, multidisciplinary approach for managing rare, complex complications. Favorable outcomes depend on close collaboration between thoracic and general surgery, with clear objectives and timely interventions at each stage.

Conclusions

We conclude that clinicians must recognize rare RFA complications and be prepared to execute a swift, appropriate, and evidence-based therapeutic sequence when they occur.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://acr.amegroups.com/article/view/10.21037/acr-2025-327/rc

Peer Review File: Available at https://acr.amegroups.com/article/view/10.21037/acr-2025-327/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://acr.amegroups.com/article/view/10.21037/acr-2025-327/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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