1 Background

Bladder cancer is the fourth most common malignancy in men and the ninth in women worldwide. Its incidence is approximately 18 cases per 100,000 individuals annually [1], often presents with hematuria, dysuria, and frequent urination. However, less commonly, it can manifest through distant complications such as thromboembolic events, including arterial embolism [2]. Acute limb ischemia (ALI) due to tumor embolism is an extremely rare manifestation of bladder cancer, and to our knowledge, this is the first reported case of acute limb ischemia caused by tumor embolism originating from bladder cancer in the literature [2, 3]. We report the case of a bladder tumor unveiled by acute limb ischemia, focusing on the mechanisms of cancer-related thrombosis and treatment strategies.

2 Case presentation

A 73-year-old male with no significant urological history, residing in a socio-economically disadvantaged area, presented to the emergency department with acute limb ischemia (ALI). He has a long history of smoking, but no other notable medical or surgical history. The patient presented with a sudden onset of severe leg pain and immobility. On examination, the left lower limb showed signs of acute ischemia, including pallor, coldness, and absent pulses. On physical examination, the patient was in considerable discomfort, with the left lower limb exhibiting classic signs of acute ischemia: pale, cold upon palpation, with absent femoral and popliteal pulses. The limb was immobile due to ischemic injury affecting nerve and muscle function, leading to paresis and paralysis. His overall systemic examination revealed no other abnormalities. Laboratory tests were part of the urgent workup aimed at excluding infection and other potential causes of the patient’s acute symptoms Laboratory tests showed an inflammatory syndrome, with an elevated C-reactive protein level of 230 mg/L. The white blood cell count was elevated at 19,410/µL, with a predominance of neutrophils. His renal and liver function tests were within normal limits. While a Doppler ultrasound could be used for a quicker diagnosis, CTA was performed to provide more comprehensive visualization of both the femoral thrombosis and the incidental bladder tumor. A contrast-enhanced computed tomography scan of the abdomen and pelvis revealed a femoral artery thrombosis, along with an incidental finding of a bladder tumor, raising suspicion of tumor embolism as the cause of the ALI (Figs. 1 and 2). The patient was promptly treated with emergency thrombectomy using a Fogarty catheter. The procedure was performed under general anesthesia and involved the insertion of the catheter through a femoral artery access point. The catheter was advanced to the site of the embolus, and the balloon was inflated to retrieve the thrombus. The embolic material was carefully aspirated, and the artery was flushed to restore normal blood flow (Fig. 3). The patient showed immediate improvement with restored pulses in the affected limb and a reduction in pain. There were no immediate complications following the thrombectomy. A resection of the bladder tumor was performed one month later. Histopathological analysis confirmed the tumor as the source of the embolism (Fig. 4). Differential diagnoses included other potential causes of ALI, such as atherosclerosis or cardiac embolism, but these were ruled out based on imaging and clinical findings. The primary diagnosis was acute limb ischemia secondary to tumor embolism originating from a bladder tumor. The thoraco-abdominal computed tomography scan, performed after the thrombectomy to assess metastasis, as part of the oncological work-up, showed multiple pulmonary and hepatic nodules suggestive of secondary lesions. At discharge, the patient was stable and had no signs of infection or re-embolization. He will continue with oncological follow-up for potential adjuvant therapies based on histopathological results. The patient received chemotherapy.

Fig. 1
Fig. 1
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Computed tomography scan findings are consistent with a 13-mm floating thrombus at the aortic bifurcation and thrombosis of the right common femoral artery

Fig. 2
Fig. 2
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Tumoral thickening with budding of the bladder wall, locally advanced (extension to the seminal vesicles and contact with the sigmoid colon)

Fig. 3
Fig. 3
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Retrieval of the thrombus from the common femoral artery using catheter-based thrombectomy: Fogarty catheter

Fig. 4
Fig. 4
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Hematoxylin–eosin × 10: blood vessel filled with hemorrhagic and fibrinous material, interspersed with clusters of urothelial carcinoma (arrow)

3 Discussion

This case underscores the importance of considering bladder cancer as a potential underlying cause of arterial embolism, its primary strength lies in the prompt diagnosis and effective intervention. While computed tomography angiography (CTA) is commonly used for diagnosing acute limb ischemia and identifying vascular lesions like aortoiliac disease or atherosclerosis, the incidental discovery of the bladder tumor on imaging was not expected and posed an additional diagnostic challenge. The Fogarty catheter thrombectomy technique was successfully employed in an emergency setting, resulting in immediate restoration of limb perfusion. However, there were also limitations inherent to this case. The primary limitation involved the potential for incomplete clot retrieval using the Fogarty catheter, particularly given the friable nature of the embolic tumor fragments. While the Fogarty catheter is effective in many cases, its ability to fully remove emboli may be limited, especially in cases of large or dispersed embolic fragments. As a matter of fact, bladder tumors, particularly invasive forms, can increase the risk of both venous and arterial thromboembolic events. This risk is primarily due to several mechanisms contributing to a hypercoagulable state in cancer patients. One significant pathway is the overexpression of tissue factor (TF) on tumor cells, which activates the extrinsic pathway of coagulation. TF binds to factor VIIa, leading to thrombin generation and the conversion of fibrinogen to fibrin, promoting clot formation. Tumor cells also produce cancer procoagulant, which activates factor X, further contributing to thrombus formation. Additionally, inflammatory cytokines such as interleukin- 6 (IL- 6) and tumor necrosis factor-alpha (TNF-α) secreted by tumor cells can activate the endothelium and increase leukocyte adhesion, promoting a prothrombotic state [2,3,4]. Moreover, tumor cells release extracellular vesicles (EVs) that contain procoagulant proteins like TF, which circulate and trigger coagulation. These vesicles can also facilitate the formation of tumor emboli, which can travel through the bloodstream and become lodged in distal arteries [5,6,7].

In this case, the bladder tumor invaded nearby vasculature, allowing tumor cells or fragments to embolize to the lower limb arteries. This embolism resulted in acute limb ischemia (ALI), a rare but potentially fatal complication. The embolic fragments obstructed the femoral artery, causing ischemia. The embolism likely occurred due to both direct vascular invasion by tumor cells and mechanical obstruction from large tumor fragments or emboli. As a matter of fact, the invasive nature of bladder cancer can lead to vascular invasion, meaning that tumor cells can invade blood vessels, detach, and embolize to distant organs, potentially causing ALI. Additionally, vessel permeation by the tumor allows for more effective spreading through the bloodstream. Tumor embolism is thus a rare but severe complication of bladder cancer, underscoring the need for high clinical suspicion when evaluating patients with unexplained arterial thromboembolic events. We performed an emergency embolectomy using a Fogarty catheter, a medical device used for thrombectomy procedures to remove emboli from arteries, successfully restoring blood flow to the affected limb. According to literature, and for cases of acute arterial ischemia caused by tumor emboli, several embolectomy techniques are employed, each with specific advantages and limitations. The primary surgical approach involves catheter-based thrombectomy using a Fogarty catheter, which is widely used due to its effectiveness in retrieving embolic fragments. The Fogarty catheter is inserted into the artery and advanced past the embolus; then, the balloon is inflated and withdrawn, pulling the embolus out. This technique is less invasive and relatively quick, making it particularly useful in emergencies. However, one limitation is the possibility of incomplete retrieval, especially if the embolus is friable or if there are multiple embolic fragments lodged in different arterial branches. Additionally, there is a risk of vessel wall injury, particularly in fragile or diseased arteries [8]. Another technique is open surgical embolectomy, a more invasive procedure than catheter-based thrombectomy, requiring an incision to directly access the embolus. This method allows the surgeon to visualize the clot, and it is particularly useful in cases where catheter-based techniques are unsuccessful. Open embolectomy has a higher success rate for complete clot retrieval and allows for more precise removal of tumor emboli, especially when they are large or adherent to the vessel wall. However, it is more invasive and carries higher risks, including potential complications from anesthesia, longer recovery time, and the need for postoperative monitoring. In patients with advanced cancer and poor overall health, this approach may be less suitable due to these additional risks [9]. In recent years, various mechanical thrombectomy methods have become available for thromboemboli removal, including aspiration thrombectomy and percutaneous mechanical thrombectomy, both of which offer effective solutions depending on the clinical context. Percutaneous devices use suction to aspirate clots directly from the artery, offering a less invasive option compared to open surgery. Aspiration devices may reduce the risk of arterial wall damage, but they are not yet widely used for tumor embolism, and their efficacy can be limited by the size and consistency of the embolus [10]. Each technique must be tailored to the patient's overall condition, the characteristics of the embolus, and the urgency of limb ischemia. In cancer-related arterial embolism, a multi-disciplinary approach is often beneficial to optimize both the immediate treatment of ischemia and the long-term management of the underlying malignancy.

4 Conclusion

ALI caused by tumor embolism is a rare but serious complication of bladder cancer. This case underscores the importance of considering malignancy as a potential underlying cause when evaluating patients with unexplained arterial thromboembolic events. Early recognition and prompt intervention, including embolectomy, can significantly improve outcomes, especially when the embolic source is identified and treated. A multi-disciplinary approach is critical in managing both the acute ischemic event and the underlying cancer. Further studies are needed to better understand the mechanisms of tumor-related thrombosis and to optimize treatment strategies for these rare yet dangerous presentations.