EPITHELIOID HEMANGIOENDOTHELIOMA OF THE LUNG IN A DOG

Epithelioid haemangioendothelioma of the lung was found in a 9-year-ol d female dog. The tumour occurred bilaterally in the form of multiple, discrete, small nodular lesions with a similar histological appearanc e. The lesions were characterized by a hypocellular sclerotic core sur rounded by a more cellular peripheral zone, from which the tumour tiss ue extended into the adjacent alveolar spaces and bronchioles in a mic ropolypoid manner, filling their lumina. In addition, invasion of the pulmonary vessels was frequently observed within, around, and at a dis tance from the nodular neoplastic lesions. Most of the tumour cells ha d abundant eosinophilic cytoplasm, large, round or oval nuclei, and oc casional intracytoplasmic vacuoles containing red blood cells. By mean s of immunolabelling, factor VIII-related antigen, a marker for endoth elial cells, was detected within the cytoplasm of a small proportion ( <5%) of the tumour cells. This appears to be the first report of such a tumour in an animal other than man. (C) 1998 W.B. Saunders Company L imited.