Isolated pulmonary hydatid cyst: Misinterpreted as metastatic pulmonary lesion in an operated case of carcinoma breast in young female

Hydatidosis is caused by Echinococcus granulosus. Humans may be infected incidentally as intermediate host by the accidental consumption of soil, water, or food contaminated by fecal matter of an infected animal. Hydatidosis is one of the most symptomatic parasitic infections in various livestock - raising countries. Lung is the second most commonly affected organ following the liver. The symptoms depend on the size and site of the lesion. It can present as an asymptomatic pulmonary lesion to hemoptysis, chest pain, coughing anaphylaxis, and shock. There are very few reported cases of isolated lung hydatidosis without exposure to animals or nonvegetarian diet. For hydatidosis, serology and imaging are diagnostic tools. Surgical removal and/or chemotherapy are the main-stay of treatment. Here, we discuss a case of persistent left lower lobe cystic lesion in young female with a history of operated left breast carcinoma which was thought to be of metastatic lesion but ultimately confirmed as pulmonary hydatid cyst after unintended aspiration of cystic fluid to rule out malignancy. Pulmonary hydatidosis should always be considered as a differential diagnosis when dealing with a cystic lesion on radiology.