Fatal Microscopic Pulmonary Tumor Thromboemboli: Unusual Presentation of Occult Cervical Carcinoma. Two Case Reports and Review of the Literature.

Cor pulmonale (right heart failure) due to microscopic pulmonary tumor emboli (MPTE) can arise from a variety of malignancies including breast, lung, and liver and carries significant morbidity and mortality. Tumor cell aggregates spread hematogenously to the lungs and occlude small pulmonary vessels leading to pulmonary hypertension through either a mechanical process or inducing vascular remodeling as a downstream result of interactions between the embolus and the vessel wall. Its presentation includes unexplained dyspnea, hypoxemia, tachycardia, pulmonary hypertension, right heart failure, and in some cases sudden death. The symptoms may suggest the more common entity of pulmonary thromboembolism, particularly in the setting of previously known metastatic cancer; however, computed tomography scans may appear normal and ventilation-perfusion scans which are the preferable diagnostic modality are not always ordered. In most cases of MPTE, the presentation reflects metastasis of an already known and advanced tumor, but, in rare cases, it may be the primary manifestation of an occult malignancy. We present here 2 unique cases of MPTE in women with occult cervical cancer. In both cases, the malignancy was discovered and diagnosed at autopsy. Microscopic pulmonary tumor emboli can be easily overlooked, and therefore, forensic pathologists and other death investigators should be aware of it and trained to at least consider the possibility in appropriate situations. Thorough microscopic examination of apparently normal tissues may be necessary, particularly in cases of unexplained right heart failure and sudden death, even if the decedent has few or no identifiable risk factors for cancer.