Papillary carcinoma in a male breast cyst: a diagnostic challenge.

Intracystic papillary breast carcinoma is a rare form of non-invasive carcinoma with an excellent prognosis. It accounts for less than 0.5% of breast cancers. We report the case of a 75-year-old man presenting with a painless cystic lump in the right breast. Ultrasonography showed a cystic lesion and aspiration revealed blood-stained fluid with suspicion of malignancy. Excisional biopsy was necessary to confirm the diagnosis and also indicated that local treatment was adequate.