Tumor microemboli to the pulmonary vasculature is described in many different cancers. This case illustrates the diagnostic and clinical challenges associated with acute cor pulmonale and rapidly progressing dyspnea in a man with a history of treated bladder cancer.
A 70 year old man presented with a six month history of nonproductive cough and progressive dyspnea. He had been treated for community acquired pneumonia, hypersensitivity pneumonitis and asthma with no improvement. Accompanying his symptoms were episodes of pleuritic chest pain and a 30 pound weight loss. His past medical history was significant for coronary artery disease, hypertension and type 2 diabetes. He was diagnosed cystoscopically with superficial bladder cancer nine months prior to presentation and treated with 5 weeks of Bacille Calmette-Guerin washings. Medications included metoprolol, salmeterol, aspirin, lansoperazole and glyburide. His occupation was as a construction worker. He had a 20 pack year tobacco history and quit 20 years ago. He had pet parakeets. He traveled to Bermuda anually. Physical exam: blood pressure 150/90, heart rate 110, respirations 24, pulse oximetry 90% on room air and 81% with exertion. Jugular venous pressure was estimated at 6cm. There was no heave or accentuated P2. Lung exam revealed crackles at the bases and mid lung fields. There was 1+ lower extremity pitting edema without clubbing. Diagnostic data included a negative serological workup for autoimmune and connective tissue disease. Purified protein derivative skin test for tuberculosis was positive. Pulmonary function testing revealed a mixed obstructive and restrictive defect and a severely diminished diffusing capacity. Electrocardiogram revealed a new right bundle branch block. Chest radiograph revealed bilateral lower lobe predominant patchy interstitial disease. Computed tomography anigiogram of the chest was negative for pulmonary emboli. Bronchoscopy was performed one day later, and revealed a monohistiocytic predominant lavage. Stains and cultures for bacteria, fungi and acid fast bacillus were negative. Biopsies were precluded by refractory hypoxemia. He was admitted to the hospital and a video assisted thoracoscopic surgical (VATS) lung biopsy was scheduled. 18 hours after admission, he was transferred to the ICU for tracheal intubation. Refractory hypoxemia and hypotension complicated his ICU course. Additional diagnostic data in the ICU included persistent chest radiograph abnormalities and negative lower extremity Doppler ultrasounds. An echocardiogram revealed a hypertrophied, dilated and hypokinetic right ventricle and no shunt. Pulmonary artery (PA) catheterization revealed right atrial pressures of 22 mmHG, PA pressures of 95/45 and PA wedge pressure of 12 mmHG. 48 hours after admission, he suffered an asystolic arrest and was not able to be resuscitated. A post mortem examination was performed.
The final cause of death was acute on chronic right heart failure secondary to diffuse pulmonary metastasis of high grade transitional cell carcinoma of the bladder with tumor microembolization to the pulmonary vasculature. This case of tumor microembolization represents a diagnostic challenge first described in 1897 by Schmidt in a small autopsy series(1). Similarly, over a century later, this diagnosis is rarely made ante mortem. Common sources include liver, breast, stomach, renal, prostate and choriocarcinoma(2). This patient was diagnosed with superficial bladder cancer by cystoscopy 9 months prior to admission. Ironically, after a 5 week course of immunotherapy, his repeat cystoscopy was precluded by dyspnea and hypoxemia.
Tumor microembolization is diagnostically challenging and almost always fatal. Diagnosis by careful aspiration of blood for cytological examination from a wedged pulmonary artery catheter has shown promise in small case report series1. Tumor microembolization should be suspected in patients with a history of malignancy, clinical signs of right heart failure, hypoxemia and a negative thromboembolic workup.
Timothy Collins, None.