A benign proliferation of the epithelium within large mammary or lactiferous ducts.
Papillomas usually arise less than 1 cm from the nipple and obstruct the natural secretions from the gland. In younger women multiple smaller peripheral ducts may be involved, termed peripheral papillomatosis. This is associated with an increased risk of developing breast cancer.
Most patients present with a bloody or serous nipple discharge. It is often possible to identify the discharge as arising from a single point on the nipple, where a dilated slitlike orifice may be visible. There may be a small swelling at the areolar margin (30%), which if pressed may produce discharge.
One to two centimetres sized papilloma within a dilated duct with secretions collected behind it. The lesion usually consists of fronds of vascular tissue covered by a double layer of cells resembling ductal epithelium. Malignant change is rare.
Mammography and/or ductography show the dilated duct and filling defect.
A wire is often passed into the responsible duct, which is excised as a microdochectomy with the breast segment that drains into it.