Diffuse pulmonary tumor microemboli from adenocarcinoma of the colon.

We have presented a rare case of pulmonary tumor microemboli from adenocarcinoma of the colon. The majority of primary tumors are adenocarcinomas, with gastric, breast, and liver carcinomas most frequently identified. Dyspnea and respiratory distress without an obvious cause is common. The history, physical examination, chest roentgenogram, ventilation-perfusion lung scan, and pulmonary angiogram are often not helpful in establishing the diagnosis. Pulmonary hypertension, present in our patient, and cor pulmonale are well described in association with diffuse pulmonary tumor microemboli. The pathologic findings are limited to the intravascular compartment exclusively, frequently in association with thrombus. The true incidence of pulmonary tumor microemboli is not known and may be underestimated. Appropriate management requires a high index of suspicion to establish the diagnosis.