Cystic echinococcosis in the neck

The diagnosis of cystic echinococcosis (echinococcus granulosus) in an atyp ical location can be difficult to make and frequently can only be establish ed by histological examination of affected tissues. Surgical excision and f ine-needle aspiration biopsy usually lead to the diagnosis. Since puncture of these cysts may cause an anaphylactic reaction due to spillage of hydati d fluid and/or dissemination of infection,the use of fine-needle aspiration biopsy is controversial at present. We report on a patient with a cystic n eck mass who developed an allergic reaction after diagnostic fine-needle as piration biopsy. Cytological examination of the specimen was inconclusive. The allergic reaction led to the diagnosis of echinococcosis, which was con firmed by serological examination. We describe a possible diagnostic proced ure for a cystic mass of unknown etiology. If imaging and serological tests are not conclusive, we believe that fine-needle aspiration biopsy is justi fied. However,this should only be performed in a setting that provides suff icient management for anaphylactic reactions.