From Suspected Bladder Cancer with Pulmonary Metastases to Necrotizing Cystitis and Septic Pulmonary Embolism: A Case of Diagnostic Reversal in a Nonagenarian
從疑似膀胱癌合併肺部轉移到壞死性膀胱炎及敗血性肺栓塞：高齡病人診斷顛覆的驚奇病例

Wei-Cheng, Chen1, 2、Yu-Hsin, Tu1、Shian-Shiang, Wang1、Jian-Ri, Li1
1Department of Urology, Taichung Veteran General Hospital, Taichung, Taiwan (R.O.C.); 2Division of Traumatology, Department of Emergency, Taichung Veteran General Hospital, Taichung, Taiwan (R.O.C.)
陳韋辰1, 2、涂妤忻1、李建儀1、王賢祥1

 1臺中榮民總醫院泌尿部；2臺中榮民總醫院急診部外傷科

Keywords: necrotizing cystitis, hematuria, elderly, pulmonary embolism, septic embolism, bladder cancer mimicry

Case Presentation

A 90-year-old female with hypertension, asthma, chronic kidney disease, and a history of pulmonary embolism (on NOAC) presented with one month of painless gross hematuria, dysuria, general weakness, and poor oral intake. Initial emergency evaluation revealed gross hematuria and a right lower lung mass on chest X-ray. Abdominal CT demonstrated irregular thickening of the bladder wall, raising suspicion for bladder tumor. Cystourethroscopy showed multiple tumor-like lesions at the bladder neck, dome, and left lateral wall, with intact bilateral ureteral orifices.

Given the high risk of urological malignancy in elderly patients with visible hematuria, the American Urological Association (AUA) and American College of Physicians recommend cystoscopy and upper tract imaging for all patients over 35 years old with unexplained hematuria, regardless of anticoagulant use.[1][4][5][21] The patient was admitted for transurethral resection of bladder tumor (TURBT). Postoperatively, transient ST depression was noted, likely due to dehydration, but cardiac enzymes remained stable. Pathology from TURBT revealed marked ulceration with acute necrotizing inflammation and granulation tissue, consistent with necrotizing cystitis, not malignancy.

During admission, lung CT revealed intraluminal filling defects in the right main/interlobar/lower segmental pulmonary arteries, consistent with pulmonary embolism and septic embolism with pneumonia. This constellation of findings—septic pulmonary embolism and necrotizing cystitis—suggests a severe, complicated urinary tract infection with hematogenous spread, a rare but recognized entity in elderly, immunocompromised patients.[3][6][7][8][9][12][13][16][19][20]

Discussion

The initial impression of bladder cancer with possible lung metastasis was based on the classic presentation of painless gross hematuria and bladder wall thickening in an elderly patient, as recommended by the AUA and American College of Physicians.[1][4][5][21] Pulmonary lesions in the context of suspected bladder cancer are often interpreted as metastatic disease, given the high frequency of lung metastases in advanced urothelial carcinoma.[10][11][22][23][24][25][26] However, the final diagnosis of necrotizing cystitis and septic pulmonary embolism with pneumonia was confirmed by histopathology and imaging, highlighting the importance of integrating clinical, radiological, and pathological data.

Necrotizing cystitis is a rare, severe form of complicated urinary tract infection, typically seen in elderly, diabetic, or immunocompromised patients.[6][7][8] It can mimic bladder cancer both clinically and radiologically. The pathogenesis involves aggressive bacterial invasion, tissue necrosis, and, in some cases, gas formation within the bladder wall.[6][8][17] Septic pulmonary embolism arises from hematogenous dissemination of infected thrombi, most commonly from sources such as liver abscess, endocarditis, or urinary tract infection.[9][12][19] The presence of pneumonia further complicates the clinical picture, as infection and inflammation are known to increase the risk of venous thromboembolism, including pulmonary embolism.[13][16][20]

Current evidence suggests that acute infections, including severe urinary tract infections, can promote a prothrombotic state through systemic inflammation, endothelial injury, and activation of the coagulation cascade, thereby increasing the risk of pulmonary embolism.[16][18][20] In this case, necrotizing cystitis likely contributed to bacteremia and septic emboli, which seeded the pulmonary vasculature and led to pneumonia. The association between necrotizing cystitis and pulmonary embolism is not well established in the literature, but the pathophysiological link is plausible given the role of infection-induced hypercoagulability and septic embolization.[16][18][19][20]

This case underscores the diagnostic challenge of differentiating malignancy from severe infection in elderly patients with hematuria and bladder wall thickening. Necrotizing cystitis with septic pulmonary embolism is a rare but important mimic of urothelial carcinoma. Early recognition and multidisciplinary management are essential to optimize outcomes.

Conclusion

This case highlights the importance of a comprehensive diagnostic approach in elderly patients with hematuria and bladder wall thickening. Necrotizing cystitis and septic pulmonary embolism can closely mimic advanced bladder cancer with lung metastases. Awareness of these rare entities and their potential association is crucial for accurate diagnosis and appropriate management.