Pulmonary tumor microembolism.

Pulmonary tumor microembolism is usually recognized as a slowly progressive syndrome of dyspnea and pulmonary hypertension in a patient with an established diagnosis of malignant disease. We have reported an extremely unusual case in which the pulmonary tumor microembolism syndrome occurred in a patient without prior history of malignancy. Further, no primary tumor could be found on postmortem examination. Clinicians should be aware that this potentially treatable entity may affect a wider spectrum of patients than has been previously recognized.