Case Presentation: A 48-year-old woman with invasive ductal adenocarcinoma of the breast presented with three weeks of progressive dyspnea on exertion and a non-productive cough. She was tachycardic and tachypneic but otherwise hemodynamically stable. Physical exam was only notable for labored breathing and obesity. Basic lab work was unremarkable. Arterial blood gas showed respiratory alkalosis with pH 7.48, pCO2 33, pO2 97. During the hospitalization, she remained tachycardic, tachypneic, and intermittently hypoxic, requiring supplemental oxygen. EKG showed sinus tachycardia and troponins were negative. Chest X-ray was negative for focal consolidations, effusions, edema, and pneumothorax. CT scans of her chest showed some mediastinal and left axillary lymphadenopathy and a 3.8 cm left breast mass, but no thromboembolus, and vascular duplex was negative for DVTs. Echocardiogram was notable for an elevated RVSP of 40-50 mmHg. High resolution CT did not show significant findings and a ventilation / perfusion scan showed symmetrical lung ventilation and perfusion. Given unremarkable workup except for an elevated RVSP, tumor emboli syndrome (TES) was considered. A right heart catheterization was performed, which showed mild pulmonary hypertension and a sample of blood from the pulmonary vasculature was positive for malignant cells consistent with adenocarcinoma. Patient was discharged on supplemental oxygen with plans to continue chemotherapy.
Discussion: Patients with TES typically present indistinguishable from other emboli syndromes: dyspnea, pleuritic chest pain, tachycardia, and acute hypoxia. Although venous thromboembolism is more common, it is important to recognize that any material larger than 10 microns can target the lungs, including air, amniotic fluid, fat, injected foreign material, and tumor. TES is the existence of tumor cells in the pulmonary vascular system and rarely involves invasion into surrounding parenchyma. Renal cell carcinoma, hepatocellular carcinoma, and adenocarcinomas are common causes of TES. Tumor can access the vessels via direct invasion, diaphragmatic translocation, or circulation into the vessels. Once the tumor cells reach the pulmonary circulation, the emboli can cause direct obstruction or activate the coagulation cascade, causing concentric medial hypertrophy and intimal fibrosis, leading to obliterative arteries. Unlike thromboemboli, tumor emboli can progress to irreversible obstruction of pulmonary vessels. In diagnosing TES, imaging and chemistry tests are not sensitive or specific, especially in the early phases of the disease. The diagnosis of TES requires histological evidence; however, due to diagnostic delay, the diagnosis is usually made postmortem, which is estimated to be as high as 26%. Transbronchial or surgical lung biopsy can be performed. Less invasively, a right heart catheterization for aspiration of the pulmonary artery can be performed. Treatment for TES is targeted at treating the primary tumor, but TES is an indicator of a poor prognosis.
Conclusions: TES should be suspected in patients with malignancy who presents with dyspnea, hypoxemia, and unexplained pulmonary hypertension. The gold standard in diagnosing TES is through histological evaluation of tissue samples.