INTRODUCTION:Acute cor pulmonale is an uncommon manifestation of microscopic tumor embolism (MTE). MTE usually presents as subacute cor pulmonale, described as rapid development of right heart failure due to tumor emboli in the lung. This manifestation, most often due to adenocarcinoma, has been described in patients with various malignancies including breast, gastric, prostate and liver. We present a case of fatal acute cor pulmonale from transitional cell carcinoma (TCC) of the bladder, which has rarely been reported in the literature.
CASE PRESENTATION:50-year-old male with a history of TCC of the bladder status post resection, radiation therapy and chemotherapy presented with sudden onset of dyspnea, fever and chest tightness. The patient was initially hemodynamically stable, with an O2 saturation of 95% on room air. The physical exam was unremarkable, significant for only crackles at the bases. An EKG showed non-specific ST-T wave changes in leads V1-V3 and sinus tachycardia. CXR showed right hilar enlargement. A CT scan of the chest showed enlargement of the main pulmonary artery and reflux of contrast into the hepatic veins. While no evidence of pulmonary embolism (PE) was seen, the index of suspicion for PE was high, thus antiticoagulation was started.A 2D-echocardiogram reported a left ventricular ejection fraction of 65%; hypokinetic dilated right ventricle, and systolic ventricular septal flattening. Estimated PAP was 86 mmHg. The patient progressively worsened, eventually requiring intubation. At this point, an arteriogram was obtained. The arteriogram revealed elevated PAP of 67 mmHg and no acute pulmonary emboli. The patient continued to deteriorate becoming hypotensive, bradycardic, and cyanotic leading to eventual cardiac arrest. Despite aggressive resuscitative efforts the patient expired. An autopsy with microscopic evaluation of the lung revealed multiple small tumor thrombi involving vessels in both lungs. Peritoneal carcinomatosis with intrathoracic and intraabdominal lymph nodes showing metastatic carcinoma was also noted.
DISCUSSIONS:Pulmonary MTE is the presence of isolated cells or clusters of tumor cells within the pulmonary arterial system.Dissemination of cancer occurs primarily via a hematogenous route. The most common site for metastasis is the lung. Three outcomes occur with malignant cells in the lung: parenchymal metastasis, invasion of lymphatics and pulmonary hypertension(PAH).Development of PAH has been attributed to two possible mechanisms: 1. Increased pulmonary vascular resistance through occlusion of the vascular bed, and 2.Vascular remodeling creating medial hypertrophy of the small arteries, intimal fibrosis and disruption of the internal elastic lamina.The incidence of MTE is reported anywhere from 3-26%. The diagnosis is difficult, often based on clinical suspicion rather than radiographic imaging. Consequently, the diagnosis of MTE is often missed.Hypoxemia with a normal chest radiograph is common. Progressive dyspnea with tachycardia and tachypnea is the most common presentation; cardiomegaly and prominent pulmonary vasculature are seen less often. CT scans and pulmonary angiography are typically non-diagnostic. A V/Q scan may have greater diagnostic utility in the diagnosis. The V/Q scan reveals multiple subsegmental mismatched defects.The use of pulmonary artery catheters may also be used to confirm malignant disease in patients with unexplained hypoxemia. Blood collected from the pulmonary port, while in the “wedged” position, can be sent for cytologic analysis. Open lung biopsy is the gold standard, however has minimal role in the acute setting. The overall prognosis is poor. Rapid deterioration with respiratory and hemodynamic failure is the typical outcome. The role of chemotherapy is usually reserved for those in the subacute setting and for chemosensitive tumors.
CONCLUSION:Acute Cor Pulmonale is an extremely rare manifestation of MTE. However, MTE should be considered in a patient with a known malignancy presenting with unexplained PAH and dyspnea.
DISCLOSURE:Tapan Desai, None.