Duct Papilloma

Duct papillomas can be solitary or multiple. These lesions can present in isolation but are often noted in association with other benign breast pathology.

Although papillary lesions are histologically similar, there are different subtypes in terms of clinical characteristics and associated risk of subsequent carcinoma.

Solitary Intraductal Papilloma

Solitary intraductal papilloma is a benign lesion arising in a single central duct.

Clinical Features

A classical symptom is spontaneous nipple discharge, which can be serous or blood stained. The discharge emanates from a single duct, and pressure over the duct at the margin of the areola usually produces copious discharge. There may be an underlying palpable mass that may represent the papilloma itself or a dilated duct proximal to the papilloma.

Radiology

Mammography
Unless the papilloma is large and the breast of predominantly fatty density, papillomas are usually not visualized mammographically. The objective of the mammogram is to rule out underlying malignancy.

Ultrasound
As with mammography, papillomas are not diagnosed reliably with ultrasound. Occasionally, they appear as a solid nodule within a fluid-filled duct.

Galactography
Galactography involves the taking of mammograms following the injection of contrast into a discharging duct. A galactogram reveals an intraductal papilloma as a filling defect either partially or totally occluding a duct. In addition, a galactogram distinguishes between troublesome discharge due to a papilloma and that due to duct ectasia. In our unit, both conditions are treated with surgical excision. The undertaking of a galactogram does not change patient management; therefore, it is not performed preoperatively.

Galactography does not reliably distinguish between a benign intraduct papilloma and a carcinoma.

Pathology

Cytologic smears of the nipple discharge may be helpful occasionally in distinguishing between benign intraductal papilloma and a papillary carcinoma.

Macroscopic Appearance
In the majority of cases, no gross abnormality is seen. This is consistent with the small size (<3 mm) of the majority of these lesions. Larger papillomas are evident as pink or deep-red velvety lesions within a dilated duct.

Microscopic Appearance
Characteristically, these lesions have an arboriform structure containing a central fibrovascular core that is covered by an inner myoepithelial and an outer or luminal epithelial layer. The epithelium may show the usual type hyperplasia, apocrine metaplasia and, occasionally, squamous metaplasia. Sclerosis of the fibrovascular core and partial or complete obliteration of the duct lumen may be seen. When these latter changes are present, the lesion is termed a ductal adenoma.