LYMPHANGIOSARCOMA IN A YOUNG-DOG

Lymphangiosarcoma was diagnosed from biopsy material obtained from an 8-week-old puppy with a progressively enlarging subcutaneous inguinal swelling. Histologically, the tumor was composed of endothelial cells immediately adjacent to large collagen bundles. Tumor cells formed irr egular vascular channels which extended along the connective tissue in vestments of small vessels and nerves of the subcutis and deep dermis. Similar neoplastic tissue extensively infiltrated an inguinal lymph n ode. Neoplastic cells were immunohistochemically stained for factor 8- related antigen and were weakly positive when compared with several he mangiomas and hemangiosarcomas. Transmission electron microscopy revea led numerous micropinocytotic vesicles and a continuous basal lamina. The puppy was euthanatized at 8 months of age due to severe septic pol yarthritis. Lymphangiosarcoma was documented at the site of the origin al tumor as well as in the axillary lymph node at necropsy.