Pulmonary tumor embolism (PTE) is an acute vascular condition caused by a sudden blockage of a pulmonary artery or vein by a clot or tumor fragment which has traveled to the lungs from elsewhere in the body.

PTE is most commonly caused by mucin-secreting adenocarcinomas of the breast, lung, stomach, and colon. Other malignancies known to cause PTE include those of the renal cells, prostate, cervix, ovaries, bladder, skin, pancreas, parotid, and thyroid, or by mesothelioma, choriocarcinoma, hepatocellular carcinoma, atrial myxoma, or Wilms tumor. PTE is an end-stage manifestation of malignancy and carries a poor prognosis, perhaps due to the association with concomitant lymphangitic or metastatic carcinoma.

PTE is typically discovered in autopsy but rarely may become clinically apparent. Clinical presentation is variable. Most patients present with progressive dyspnea. Pleuritic chest pain is common. Less frequently occurring symptoms include fatigue, weight loss, cough, and hemoptysis. Tachycardia is usually apparent upon physical examination. Some features of pulmonary hypertension and cor pulmonale include increase in the pulmonic component of the second heart sound, a right ventricular lift, cyanosis, and jugular venous distention. The majority of PTE cases are detected in patients with a known malignancy; however, in rare cases, PTE may be the presenting manifestation in an occult neoplasm.