The authors report the case of a 56-year-old woman with mammary sparganosis due to infection with a plerocercoid tapeworm larva of Spirometra mansoni. Magnetic resonance imaging revealed an area of heterogeneous density in outer upper quadrant of the right breast, with a high likelihood of malignancy. During surgery for the removal of a granuloma, the parasite was discovered and excised. The authors review the pathological and imaging feat...