<unk><unk>  is an rare ductal malignancy, accounting for 1%–2% of<unk> <unk> s.<unk><unk> s may be solitary or multiple. When the epithelium of a<unk><unk>  has features diagnostic of intraductal<unk> , the lesion is classified as<unk>  ductal<unk>  in situ. If a cystic component is present, the tumor is described as an intracystic<unk><unk> . In the absence of an appreciable cyst, a diagnosis of solid<unk><unk>  is appropriate. Invasive elements arising in a<unk><unk>  are almost always detected at the periphery of the lesion.<unk><unk> s are usually well circumscribed and often contain hemorrhagic and cystic areas. The mean patient age at diagnosis of<unk><unk>  is 63–67 years. Approximately 50% of<unk><unk> s arise in the retroareolar region of the<unk> .<unk><unk>  may manifest clinically as a palpable mass or nipple discharge, with the latter present in 22%–34% of patients.
Papillary carcinoma of the breast
Mammary ductal carcinoma
Breast abscess
Duct ectasia of breast
Paget's disease of the breast
Solitary mastocytoma
Mycetoma
Melanoma