Vascular intimal carcinomatosis: an autopsy case of unusual form of pulmonary metastasis of transitional cell carcinoma.

A 44-year-old woman with an unusual form of pulmonary metastasis is described. She presented with pulmonary thrombosis and clinical signs of disseminated intravascular coagulation (DIC) and died of cerebral hemorrhage. The autopsy study revealed transitional cell carcinoma of the left renal pelvis with pulmonary thrombosis in the large arteries. The intima of the vessels were intact on gross inspection except where the thrombi adhered to. The thrombi contained no tumor cells. However, microscopic examination identified that the metastatic carcinoma diffusely replaced the endothelium and proliferated on to the intimal surface without invasion of the wall and metastatic nodules in the parenchyma. Other examined organs had neither primary nor metastatic tumors, except for microscopic metastasis to the inferior vena cava. To date, this pattern of metastasis has not been noted in previous literature. This condition was designated as being vascular intimal carcinomatosis because of its characteristic manner of tumor proliferation on vascular intima.