EN
Authors describe a rare case of occurence of Tetrathyridium elongatum (Blumberg, 1882) a larvae of tape-worm Mesocestoides lineatus in pleural and peritoneal cavity in a dog. These parasites amounted to 50 and were lying free. Also in the parenchyma of liver and pancreas a number of these parasites was found encapsulated inside cystic formations. No reaction on serous membrans was found. Histological examination of tissues in which parasitic cysts were found showed lesions similar to those caused by Echinococcus.