A chest wall swelling in a young girl

To the Editor: Humans may serve as intermediate hosts in hydatid disease, a parasitic infection caused by the tapeworm Echinococcus granulosus. They are infected through contact with infected dogs or by ingestion of tapeworm eggs in contaminated food, water, or soil.1 The larvae form cysts in body organs. Although the liver is the most common site, lung cysts are seen in up to 30% of cases of hydatid disease. Lung cysts are generally asymptomatic, but symptoms occur if the cysts rupture.2 Here, we describe an adolescent girl with a lung cyst that ruptured across the thoracic cage into the subcutaneous fascia, presenting as a breast swelling.