Hydatid cyst: primary diagnosis by fine-needle aspiration biopsy.

Two cases of soft-tissues echinococcosis are presented in which the definitive diagnosis was established by identifying laminated layer remnants on fine-needle aspiration smears. Large polygonal pieces of acellular material with delicate parallel striations were seen, while neither scolices nor hooklets were found. The cases reported most likely represent the occurrence of sterile hydatid cysts. A diagnosis of echinococcosis should be considered when fragments suggestive of laminated layer are identified on smears, even in unusual sites and without evidence of hooklets and/or scolices.