A Cystic Mass does not Always Mean Hydatid Cyst in Endemic Areas.

Within the medical community, there is a tendency to describe all cystic lesions in the liver and lungs as Hydatid disease (HD) in areas with HD endemics. This approach may sometimes cause a misdiagnosis. We have three cases with children aged between seven, seven and ten year old, all of whom had been diagnosed, via radiologic imaging, with HD cysts and started on treatment without confirmation. The true diagnoses of these cases were undifferentiated embryonal sarcoma (UES) in two and oesophageal duplication in one case, respectively. The indirect haemagglutination assays (IHA) were obtained in two of them. Although their results were negative, albendazole treatment was started in all cases. Confirmatory tests should be run in dubious cases. An IHA test can aid the diagnosis, although its effectiveness is limited. The possibility of false positive and negative results always exists, especially in lung cysts. A percutanous biopsy is strongly advised for differential diagnosis.