[Case report: Diagnosis under the microscope - disseminated echninococcosis, the multilocular form with protoscoleces].

Echinococcosis (hydatidosis) is a rare severe tissue parasitosis. In the Czech Republic it is caused by two species of tapeworm: Echinococcus granulosus or Echinococcus multilocularis. The species differ in both their usual hosts during their life cycle as well as in the typical form of lesions in infested tissues. In both cases the liver is the most common primary infested organ.We describe an autopsy case of a massive hepatic parasitic lesion in an 81 year-old man. There were metastatic parasitic cysts in both lungs and the hepatic mass spread per continuitatem in the right adrenal gland. The lesion was microscopically represented by small cystic forms with PAS positive laminar membranes and frequent occurrence of protoscoleces in the peripheral parts of the liver and the adrenal gland.The diagnosis of echinococcosis was settled after microscopic exploration of necroptic material. The overall appearance and pattern of spreading corresponded to alveolar echinococcosis, however the massive presence of protoscoleces in the liver is very rare for E. multilocularis. Protoscoleces are usually found in infections caused by E. granulosus. Cystic echinococcosis typically presents with one larger cyst or a small number of bigger cysts with prominent fibrous rim. Because of the unavailability of molecular diagnostic methods (PCR, immunohistochemistry), that are able to distinguish individual species of parasite, the case was closed according to the typical histological findings as disseminated alveolar echinococcosis with the rare appearance of protoscoleces with possible association with immunosuppressive therapy.We have found about ten other cases of alveolar echinococcosis published in last ten years in the Czech Republic. All these cases were diagnosed in living patients. It is assumed that most of these patients were infected in the vicinity of their homes.