RESUMEN
Hydatid cyst of the breast is extremely rare even in endemic areas and it only accounts for 0.27% of all hydatid cyst disease cases. It can either be a primary site or part of a disseminated hydatidosis. Surgery remains to be a treatment of choice. Only few reports are published in the literatures and most of the reported cases have been diagnosed postoperatively as it is not easy to reach at a definitive diagnosis with clinical examination and radiological investigations only. This is a case of an isolated hydatid cyst of breast in an 18-year old woman from the Amhara region, Ethiopia. She presented with left breast painless lump of 5 years duration and a correct pre-operative diagnosed was made by fine needle aspiration cytology, then confirmed after surgery. We believe this disease should be included in the differential diagnosis of benign breast lumps especially in endemic areas.