PATHOLOGY OF THE PULMONARY-ARTERIES IN MA LIGNANT NEOPLASMS OF THE LUNG

A study was undertaken to analyse the type and extent of pathological changes in the pulmonary arteries in non-small cell malignant tumours of the lung. Large-section histological preparations were made from 33 squamous cell carcinomas and 30 adenocarcinomas (T1 and T2 tumours) a nd classified according to tumour margin area (zone 1), intermediate a rea (zone 2) and tumour centre (zone 3). Transmural tumour growth with intraluminal cell formations in the pulmonary artery branches were fo und in the centre of all adenocarcinomas and 86% of squamous cell carc inomas, involving subsegment, prelobular and lobular arteries. Obstruc tive and obliterative changes in the pulmonary arteries as the result of tumour compression and secondary fibrosing changes predominantly oc curred in the centre of all tumours. They were less common and less ma rked in zones 1 and 2. - Pulmonary artery branches in lung tumours of stages T1 and T2 showed marked infiltrating, obliterative and secondar y inflammatory changes as far as complete vascular occlusions. These o bservations indicate that cytotoxic drugs, introduced via the systemic circulation, cannot reach and therefore not exert their effects in ex tensive areas of tumour.