A papilloma is a benign growth in a breast ducts which presents in 'finger-like' fronds, and often completely blocks the duct. They are composed of 'mammary epithelium', which are the cells that comprise most of the breast duct-wall linings. Because it is a hard, new-cell growth (as opposed to something that was fluid-filled), a papilloma can be suspicious for breast cancer until it is properly analyzed. A papilloma itself is benign, but they are suspicious of a situation where cancer might develop, especially when they seem to be occuring in multiples. Papillomas tend to develop in women in the 35-55 age range.
Intraductal (breast) papillomas are not at all related to the
'papilloma's (otherwise know as 'warts'), which occur and skin surfaces and
are caused by exposure to the Human Papilloma Virus (HPV). They simply share
the name because they have similar features.
A papilloma can present as a small 'outward curved' bump, and it can either be growing on the surface of the breast or within the breast ducts themselves and visible only on mammography or by a microscope. A papilloma will generally form right around or below the nipple. A woman may discover a small lump herself, and often a clinical physician can find a tumor just beneath the surface through delicate palpation (feeling and pressure). Papillomas can also be painful. A papilloma will usually involve a nipple discharge, sometimes of serous fluid but sometimes with blood as well. ( About 1/2 of the time the nipple discharge contains blood) Sometimes nipple discharge is called "pathological nipple discharge" or 'PND', and this symptom accounst for about 5% of all women who attend breast cancer screening clinics, and between 40-70% of women who present with this symptom (PND) end up being diagnosed with papilloma. Sometimes, however, pathological nipple discharge is associated with either 'in situ' or invasive breast cancer, so it is a serious symptoms that has to be fully investigated. The rate of PND associated with breast cancer is hard to know for sure; some studies place it at over 20%, but a large, comprehensive study would probably place the rate considerably lower.
There are two basic 'categories' of breast papilloma development: Those which occur as 'solitary', or those which occur in 'multiples'. The solitary papillomas are more prone to nipple discharge, and tend to involve a papillary epithelial growth which has 'punctured' a major breast duct just below the nipple. Generally speaking, solitary papillomas are benign and not worrisome. The tumor might be drained by excision or by needle aspiration, (and given a histological evaluation just to be sure), and most of the time will not even required routine-scheduled follow-up. Many physicians don't even consider a solitary papilloma as a 'true disease' process.
Multiple breast papillomas present a different risk and management context. Here the tumors occur deeper with the breast and probably will not cause nipple discharges. Multiple papillomas form a subset of about 10% of all intraductal papillomas, and also tend to be seen more frequently in younger women. Multiple papillomas are quite often 'bilateral' (occuring in both breasts). Sometimes the physical 'placement' of one of a multiple of papillomas will be given a particular name. "Central" papillomas grow deeper within the breast, while "peripheral' papillomas are growing toward the outer edges of the breast. Some physicians argue that there needs to be at least five clearly separate papillomas within a given segment of breast tissue in order for the tumor to be termed 'papillomatosis'. Multiple papillomas are more suspicious for subsquent breast cancer development than solitary papillomas.
When a papilloma tissue sample is sent for microscopic evaluation, the pathologist may be looking for signs of 'atypia'. Sometimes, within the context of the presentation of 'multiple' papillomas, cellular atypica may already be present or may develop over time. These atypical cellular features may include hyperchromatic nuclei, marked nuclear atypia, cribriform patterns, a monotonous cell population, and absent supporting stroma. When enough atypical features are present, the phyicians may begin to classify the papilloma as 'atypical ductal hyperplasia' or ADH, which a more serious, higher-risk diagnosis, and will be screened and treated more aggressively from that point on.
Papillomatosis or 'multiple papillomas' tends to effect a slightly younger age group then solitary papillomas, but sometimes the condition can effect very young women, even as young as 10 years old. The mean age of diagnosis age tends to be in the early 20s. This 'juvenile papillomatosis' often includes a painless mass that is first dismissed as fibroadenoma. Juvenile papillomatosis tends to have many features of atypical hyperplasia, and also some cyst development. Juvenlie papillomatosis is not breast cancer, but there is increased risk for breast cancer development, especially if it is bilateral. Family history also tends to play a role in increased risk or tendency or papillomatosis to develop into breast cancer. There is even some evidence to suggest that a young patients female relatives might be more succeptible to breast cancer development than the average population, though no one knows why this is.
Any kind of proliferative cell growth in the breast raises concerns of occult breast cancer or increased risk for future breast cancer development. Fibrocystic changes of any sort are thought to confer a slightly increased risk of breast cancer development over the long term, but only slighly higher than for the general population. A solitary papilloma is considered to be benign, and the only increased risk of breast cancer would be that same, slight increase for all women who show any benign fibro-cystic change. Multiple papillomas, however, are associated with increased risk for breast cancer development, but still very low. If any of the papillomas show 'atypical' cells or cell formations, the risk is significantly higher, and we may in fact be speaking about a different diagnosis altogether, i.e. atypical ductal hyperplasia.
However, recent studies have pointed to diagnostic and assement innaccuracies associated with papillomas and breast cancer risk. It is now suspected that most instances of papilloma and papillomatosis which have 'evolved' or 'developed' into breast cancer, were actually breast carcinoma to begin with and simply under-diagnosed. Where there is strong correlation between mammographic studies and microscopic studies that convincingly point to a benign tumor, there is very low risk of subsquent breast cancer appearance. In any event, annual follow-up for multiple papillomas is a prudent course of action.
Mammograms and ultrasounds are not necessarily that useful in diagnosing a papilloma. A mammogram will generally be performed regardless as a percaution in any lesion involving bloody discharges, but intraductal papillomas do not tend to show up well on a mammogram. Papillomas tend to be small, and unless there is a large suspected 'fat' element or a somewhat larger lump, the breast x-ray might be bypassed. Ultrasound also does not reliably diagnose a papilloma. Ultrasound is generally used to get a reading on the relative amounts of fluid,solid, and fat elements in lesion, and can readily determine is a suspected lesion is a benign cyst (fluid filled). Papillomas are generally non-liquid but do occasionally appear as solid nodules within a fluid-filled duct, and some papillomas may present with cystic elements.
MRI is an extremely senstive diagnostic imaging tool and can sometimes reveal features of a papilloma 'hidden' to other views, but there is quite a range in possible appearances of a papilloma. MRI might reveal some 'atypical' or irregular enhancements that cannot reliably be distinquished from malignant cell growth, so biospy will be needed anyways. But, MRI can clearly show the total absence of atypical features surrounding the papilloma is that is the case, and this can be very reassuring for a patient. However, given the high cost and sub-optimal specificity, MRI is unlikely to be used for most suspected breast papillomas.
Breast ductography is an established diagnostic technique that is sometimes use for women who present with nipple discharges. Ductography (also called galactography or ductogalactography) basically involves injecting a 'contrast enhancing' die or substance directly into the breast ducts and then performing an X-Ray. This allows the physician to follow the course of fluids through the ducts and determined where there is any blockage. A simple, solitary papilloma will quite easily be observed as a 'blocked duct'. Multiple papillomas can also be observed as absent or sub-segmental distribution of fluid in the branching ducts; there will be a typical and identifiable pattern. Ductography might also detect the presence of malignant processes, through distortions, narrowing, and obstruction of various ducts. However, ductography has considerable limitations at arriving at a definitive diagnosis, so it is no longer a widely practiced procedure.
Breast papillomas will typically have a characteristic 'arboriform' ( tree like, or frond like) structure with a central fibrovascular core. ( combination of fibrous tissues and blood supply elements) The lesion may also have an inner myoeptihelial and outer luminal epithelial layer. The epithelial elements might show generic-type hyperplasia, apocrine metaplasia, and rarely squamous metaplasia. Sclerosis, or hardening of the fibrovascular core is common, as well as complete or partial obliteration of the duct lumen.(total blockage). When the hardening and blockage aspects seem to be the dominant features of the tumor, it might be classified as ductal adenoma. Microscopic analysis of a suspected papilloma or follow-up evalution of a confirmed papilloma might also reveal atypical hyperplasia features, or even in situ carcinoma, (DCIS) and will be classified and treated accordingly.
When confronted with 'papilloma-like' symptoms, a pathologist to make a differential diagnosis between benign papilloma on the one hand, and malignant micropapillary DCIS on the other. Both diseases have similar frond-like features. The 'Transitional epithelium' in some less-typical papillomas can resemble micropapillary DCIS cells. However, there does not appear to be any relationship between papilloma and micropapillary dcis. One can be misdiagnosed as the other, and sometimes carcinoma can arise 'de novo' (on its own, from the beginning) from the same areas as a papilloma, but there appears to be no 'disease-related' connection between them. A papilloma is not part of a micropapillary DCIS scenerio and does not 'evolve into' micropapillary DCIS or papillary breast carcinoma.
Solitary papillomas, if there are no functional complications or atypical features, will often just be left alone. If there is nipple discharge, the lesion will first be drained, and quite likely surgically excised. Often a small incision is made at the edge of the areola and the resulting scar tissue is virtually unnoticeable.
Treatment of multiple papillomas can be a bit of a grey area and judgement call. Since the only real treatment for papillomatosis ( multiple papillomas) will be mastectomy, this is a decision which tends to be delayed as much as possible. Papillomatosis will be carefully followed-up by annual checkups. If there is no evidence of atypical or malignant processes, there really is no clear reason to do anything. Where there an associated bloody nipple discharge with papillomatosis, that does tend to indicate a more suspicious situation and if it is an ongoing thing, mastecomy might be considered. However, there are new treament techniques such as the "microdochectomy", which is the surgical excision of the major effected breast duct and not the entire breast. That might be a prudent treatment option for localized, suspicious papillomas with discharges.
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