Hydatid cyst of parotid: Report of unusual cytological findings extending the cytomorphological spectrum.

Hydatid disease is a zoonotic infestation caused by larval cestode of genus Echinococcus. Cystic form of this infection mostly involves liver and lung. Hydatid disease of the parotid gland is very rare even in endemic areas and is often clinically mistaken for parotid tumors or cysts. The presence of protoscolices, laminated membranes, and isolated hooklets are characteristic cytological features observed on fine-needle aspirate from hydatid cysts. We report unusual cytological features from a hydatid cyst of parotid in a 13-year-old girl. She presented with a slowly enlarging hard mass in left parotid. Fine-needle aspiration yielded slightly turbid fluid. Smears from the sediment revealed naked parasitic micronuclei, fragments of germinative layer (endocyst), and abortive brood capsules (buds from endocyst) seen as spherical structures with multiple parasitic nuclei. Some of these spherical structures were degenerated with recognizable nuclei and others were completely necrotic. Diagn. Cytopathol. 2016;44:770-773.