COR PULMONALE is usually classified into the acute, subacute and chronic types. Acute cor pulmonale is generally caused by massive pulmonary emboli. If over 60 per cent of the vascular bed is occluded in this form, death will result almost immediately. The subacute form, the least frequent of the three, has been accurately described by Greenspan.¹ Secondary endolymphatic carcinomatosis of the lungs is the commonest cause of subacute cor pulmonale. In this condition the metastatic carcinoma diffusely infiltrates the perivascular lymphatics and then secondarily involves the pulmonary arterioles. This involvement interferes with the flow of blood through the pulmonary circuit and results in an increased burden on the right ventricle with eventual failure. The primary site for this type of secondary carcinomatous involvement of the lung is most often in the stomach, but in our experience carcinoma arising in the prostate, liver, kidney, breast or bronchus has also given