A case of disseminated peritoneal echinococcosis localized in the small pelvis and ovary was diagnosed in a 12-year old girl. Secondary hydatid echinococcosis following the rupture of a primary liver cyst was presumed. A morphological differential diagnosis of the unilocular and multilocular or alveolar echinococcus in biopsy material was considered. Finding of a protoscolex or at least chitin hooklets suggests a hydatid echinococcus, whereas alveolar or multilocular echinococcus does not produce protoscoleces in humans, hence the absence of their hooklets in the material is considered an important morphological diagnostic criterion.