A nipple adenoma is a benign epithelial cell proliferation that frequently develops beneath the areola, or nipple. An “adenoma” can occur anywhere in the body that has glands, and most breast adenomas are referred to a ‘fibroadenomas‘. Essentially they are a disorganized combination of fibrous, glandular, and fat tissues, and depending upon which one of those features is the most prevalent, it may have a more specific name. But a nipple adenoma is named according to the location of the lesion; below the nipple. An adenoma beneath the nipple can cause skin irregularity and nipple erosion, and may also result in fluid and bloody discharges.
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How is a nipple adenoma evaluated?
Normally a biopsy will be needed to confirm nipple adenoma, usually accompanied by corresponding breast X-ray and ultrasound imaging studies. Breast adenomas can initially mimic breast cancer because they appear so disorganized and also because they have a combination of solid and fat elements. Nipple adenomas are typically characterized histologically by proliferating epithelial cells and small pseudo-ductal structures that invade the surrounding stroma. These new ducts are typically lined with a double layer of epithelial cells. Small keratin cysts and ‘apical snouts‘ (proteins revealed by a staining dye, on the ‘top layer’ of the tissue) are also characteristic. There may be variable amounts apocrine metaplasia, squamous metaplasia, and sclerosis (hardened keratin).
There are two distinct types of nipple adenoma; ‘florid papillomatosis‘ and ‘syringomatous adenoma‘. The florid papillomatosis is by far the more common of the two types of nipple adenoma, and the condition is also sometimes called ‘papillary adenoma of the nipple‘, or ‘erosive adenomatosis‘. Essentially it is a proliferative growth of small breast ducts and hyperplastic epithelium which forms into a well-circumscribed, non-encapsulated mass. If some of these new ducts come into contact with the surface of the nipple they can actually begin to replace the normal epidermal (skin) covering, and give an appearance of nipple erosion. Sometimes these lesions have ‘papillary projections‘ (finger-like growths) of epithelial cells into the lumen of the new and existing breast ducts. Florid papillomatosis is benign but man mimic “Paget’s disease“, and is also pathologically similar to low-grade adenocarcinoma, so it has to be carefully evaluated.
Syringomatous adenoma (infiltrating syringomatous eccrine adenoma) is different from florid papillomatosis firstly due to an absence of ‘intraductal‘ epithelial hyperplasia, and secondly because of its unique growth pattern of oval, elongated ducts. (from the Greek term ‘syrinx‘ or ‘like a pipe‘) Sometimes the shape of these compressed ducts looks like a ‘comma‘. Eccrine cell involvement (apocrine metaplasia) is also not uncommon in these lesions. Syringomatous adenomas are thought to be a little more serious and aggressive as they tend to be more infiltrative and invasive (but just locally; they do not metastasize). Additionally, there is some speculation that a syringomatous adenoma might be related to a low-grade adenosquamous carcinoma of the breast developing in a different location. Syringomatous adenoma lesions are also similar pathologically and radiologically to microcystic adnexal carcinoma and sclerosing syringomatous carcinoma, underscoring the need for a thorough workup.
Treatment and follow-up for nipple adenoma
Nipple adenomas need to be checked and rechecked to ensure that the tumor is neither ‘overestimated‘ (assumed to be adenocarcinoma or Paget’s disease) resulting in unnecessary mastectomy, or underestimated (ignoring the possibility of slowly developing coincident epithelial malignancy). Breast adenomas are not cancerous or ‘pre-cancerous‘ in any way, but, there is a remote chance that carcinoma could be simultaneously developing somewhere in the epithelial tissue at a slower rate. While adenomas are often simply ‘left alone‘ , nipple adenomas are commonly treated by complete excision of the tumor with normal surgical margins. Even though a nipple adenoma is benign, if the tumor grows it can become painful and prone to bleeding. Recurrences are rare, but have been noted in incompletely excised lesions.
Let’s go over some of the common Q&A below…
- What are the signs and symptoms associated with nipple adenomas? They may be felt as a lump under the nipple or areola. They also may come to attention because of nipple pain, ulceration, swelling and/or discharge.
- At what age is nipple adenomas more present? They can occur at any age including the elderly, in adolescence, and in infants. However, they most commonly occur in 30-40 year old women, they can also occur in men as well.
- How is nipple adenomas diagnosed? Differential diagnosis, imaging, and biopsy.
- What is the nipple adenomas prognosis? Nipple adenomas are non-cancerous growths, which can recur if not completely surgically removed. There are reported cases of cancers arising within nipple adenomas, and following excision of nipple adenomas, but these are rare occurrences.
- How is nipple adenomas treated? Complete surgical excision is recommended.
- Odashiro, M., Lima, MG., Miiji, LN., Odashiro, DN., Carvalho, GVS., Campos, JCP., Odashiroo, AN., Infiltrating Syringomatous Adenoma of the Nipple. The Breast Journal (May 2009) Volume 15 Issue 4, Pages 414 – 416
- Brownstein MH, Phelps RG, Magnin PH. Papillary adenoma of the nipple: analysis of fifteen new cases. J Am Acad Dermatol. 1985 Apr; 12(4):707-15.
- Interlandi A, Busacca G. Adenomas of the nipple. Minerva Chir. 2002 Oct;57(5):699-702.