| Print Date: | May 22, 2013, 1:43 pm |
| Title | Intracystic Papilloma, Breast |
| Text | One of the most common causes of a serous or bloody nipple discharge is the large duct papilloma, a benign proliferation of ductal epithelium that projects into the lumen of the duct and is connected to the epithelium by a fibrovascular stalk. Usually found in the subareolar region within a major lactiferous duct, solitary papillomas can grow large enough to be visible by imaging methods when they distend the duct. They are only occasionally palpable. As noted earlier, these represent a proliferative process, and their presence signifies a slightly increased risk of breast cancer that ranges from one and one-half to two times the risk of a woman who has nonproliferative changes. These lesions are unlikely to be “precursor” lesions, but their development may indicate an unstable epithelium that may be slightly more prone to malignant transformation.
Intraductal papillomas, as their name implies, are contained within the duct. They commonly extend longitudinally through its lumen and are found only on microscopic section. They are either discovered coincidentally in a biopsy for some other reason or they cause a serous or bloody nipple discharge. Some pathologists believe that their vascular supply is fragile, which leads to areas of necrosis, infarction, and bleeding (and possibly the calcification that is occasionally seen by mammography). The duct around them can dilate and form a cystic structure. This is the origin of the intracystic papilloma. Histologically, they are differentiated from papillary carcinomas by the presence of a myoepithelial layer. Intraductal papillomas are usually solitary, but they can be multiple. The latter should not be confused with papillomatosis, which is a form of epithelial hyperplasia. Pathologists have not agreed on the description of papillomatosis. Solitary papillomas are usually in the subareolar region, whereas multiple papillomas are usually more peripheral. Rosen and Oberman suggest that women with multiple papillomas are usually younger than those with solitary papillomas. Solitary intraductal papillomas are generally discovered in the peri- and postmenopausal years. Multiple peripheral duct papillomas are less common and are believed to arise in the TDLU. Multiple peripheral duct papillomas are associated with an increased likelihood of atypical changes and carcinoma. Because they are confined within the duct and conform to it, most papillomas are not visible by mammography. They frequently extend over a long length of the duct lumen without expanding it and may follow segmental branches. Occasionally they will present as a lobulated mass distending the duct and forming a fairly well-circumscribed mass , but these cannot be differentiated from other lobulated lesions. When visible, they are almost always in the anterior part of the breast because they are usually lesions of the large ducts. Sometimes they are found within a cyst, and it is the cyst that is evident on the mammogram. Although these are called intracystic papillomas, they are actually cystically dilated portions of the duct containing a papilloma. The origin of these cysts is likely different from the cysts that arise in the lobule. The role of obstruction in the formation of these cysts is unclear. Although they can occasionally be found in the nipple itself, papillomas usually develop in the large duct several centimeters proximal to the nipple. The duct is sometimes dilated in association with a papilloma, but the papilloma is usually not right in the distal portion of the dilated duct (near the nipple), making it unlikely that the duct is dilated due to obstruction. Because the ducts are almost always obstructed by keratin plugs in the nipple, cystic ductal dilatation is likely more complex than mere obstruction: It is likely due to a combination of increased secretion (perhaps from the papilloma or irritation due to it) that is not balanced by resorption, causing the duct to dilate in accordance with Laplace’s law (its widest portion). |
| References: | |
| Contributor | Reginald L. Baker (National Capital Consortium) |
| Peer Reviewer | Claudia E Galbo (Uniformed Services University) |
| Record Number | : 5540 |
| Created | 2004-03-05 22:54:20-05 |
| Modified | 2004-03-23 04:12:00-05 |
| Category: | Neoplasm, NOS |
| Location: | Breast and Mammography |
| Sublocation: | None Selected |
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